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Zimmermann telegram

The Zimmermann Telegram was a coded diplomatic message dispatched on January 16, 1917, by Arthur Zimmermann, the German Secretary of State for Foreign Affairs, to Heinrich von Eckardt, the German ambassador to Mexico, proposing a military pact whereby Mexico would join Germany in attacking the United States if the U.S. declared war on Germany, with promises of financial support and the return of Texas, New Mexico, and Arizona to Mexican control.^[1]^[2] The proposal also urged Mexico to enlist Japan's aid in the conflict, reflecting Germany's strategy to divert American resources amid its planned resumption of unrestricted submarine warfare.^[1]^[3] Intercepted by British naval intelligence operatives in Room 40 as it traversed neutral telegraph routes via the U.S. and Sweden, the telegram was decrypted using captured German codes, revealing the audacious scheme just weeks before the U.S. anticipated entry into World War I.^[4]^[3] To preserve the secrecy of their codebreaking capabilities, British authorities relayed the decoded text to the American government on February 24, 1917, framing it as obtained through Mexican intermediaries rather than direct interception.^[4]^[2] Public disclosure of the telegram's contents on March 1, 1917, by U.S. President Woodrow Wilson ignited widespread outrage, confirming its authenticity when Zimmermann himself admitted it during a Reichstag address on March 29, thereby eroding isolationist sentiment and accelerating congressional momentum toward war declaration against Germany on April 6.^[4]^[3] This intelligence windfall exemplified the pivotal role of signals intelligence in altering the war's trajectory, though its interception stemmed from systemic German diplomatic vulnerabilities exposed by Allied cryptanalytic prowess.^[4]^[3]

Background

World War I Context and US Neutrality

By late 1916, the Western Front had devolved into a protracted stalemate characterized by entrenched positions and attritional battles, following the inconclusive outcomes of the Battle of Verdun (February to December 1916, resulting in approximately 700,000 casualties) and the Battle of the Somme (July to November 1916, with over one million casualties combined for both sides).^[5]^[6] These engagements exemplified the deadlock of trench warfare, where machine guns, artillery, and barbed wire prevented significant advances despite massive resource commitments, leaving the Allied Powers (primarily Britain, France, and Russia) increasingly reliant on external support to sustain their efforts.^[7] The United States maintained official neutrality since President Woodrow Wilson's proclamation on August 4, 1914, emphasizing impartiality in the European conflict while American banks extended substantial loans—totaling over $2 billion by early 1917—to the Allies for purchasing munitions, food, and raw materials, which bolstered Allied logistics without direct military involvement.^[8]^[9] This economic engagement reflected underlying pro-Allied sympathies among American elites, driven by cultural affinities with Britain and France, though public opinion remained predominantly isolationist, with surveys indicating sympathies favoring the Allies by roughly five-to-one among those with preferences, yet a majority advocating non-intervention.^[10] Wilson's reelection in November 1916, by a narrow margin of about 600,000 popular votes, hinged on the Democratic slogan "He Kept Us Out of War," appealing to widespread domestic aversion to entanglement amid ongoing European carnage.^[11] Neutrality faced repeated strains from German submarine warfare, notably the sinking of the RMS Lusitania on May 7, 1915, by U-boat U-20 off Ireland's coast, which killed 1,198 people including 128 Americans aboard the British liner en route from New York to Liverpool, prompting U.S. diplomatic protests but no rupture in relations as Wilson pursued mediation efforts.^[12] Further escalation occurred with the March 24, 1916, torpedoing of the French passenger steamer Sussex, injuring Americans and leading to Wilson's "strict accountability" ultimatum, which elicited Germany's Sussex Pledge on May 4, 1916, committing to forego unrestricted submarine attacks on passenger and merchant vessels without warning and search, thereby temporarily preserving U.S. non-belligerency.^[13]^[8] These incidents highlighted the tension between isolationist ideals and the practical challenges of enforcing neutral rights amid Allied dependence on American commerce.^[14]

German Strategic Pressures and Submarine Warfare

The British naval blockade, implemented from November 1914, progressively strangled Germany's access to overseas imports, exacerbating raw material shortages and food rationing that intensified by 1916.^[15] Industrial output declined due to coal and steel deficits, while agricultural imports plummeted, forcing reliance on inadequate domestic substitutes like turnips during the harsh 1916–1917 winter, known as the Steckrübenwinter.^[16] Civilian hardships mounted, with the German Board of Public Health estimating 763,000 deaths from starvation and related diseases by December 1918, though postwar analyses attribute part of the malnutrition to inefficient domestic distribution alongside blockade effects.^[17] These pressures reshaped German strategy under the Third OHL, led by Field Marshal Paul von Hindenburg and General Erich Ludendorff after their August 1916 appointment, which sidelined Chancellor Theobald von Bethmann Hollweg's restraint.^[18] The High Command calculated that unrestricted U-boat warfare could sink 600,000 tons of Allied shipping monthly, starving Britain into submission within five to six months and forcing a favorable peace before substantial U.S. reinforcements arrived.^[19] Despite intelligence assessments predicting American belligerence—evidenced by U.S. protests after the 1915 Lusitania sinking and 1916 Sussex pledge—the military prioritized offensive escalation over diplomatic concessions.^[20] Foreign Secretary Arthur Zimmermann, appointed in November 1916, navigated these tensions by endorsing the submarine campaign while advocating auxiliary diplomacy to offset U.S. involvement, including overtures to peripheral powers for potential alliances that could fragment American focus.^[4] Internal deliberations, culminating in the January 9, 1917, Crown Council meeting under Kaiser Wilhelm II, revealed divisions: naval advocates like Admiral Henning von Holtzendorff promised decisive results, overriding Foreign Office warnings of U.S. economic and military mobilization risks, with the policy formally resuming on February 1, 1917.^[19] This gamble reflected causal prioritization of immediate Allied disruption over long-term neutrality preservation, viewing U.S. entry as survivable given Britain's own blockade-induced vulnerabilities.^[20]

Composition and Transmission

German Motivational Factors

Germany's decision to issue the Zimmermann Telegram stemmed from acute strategic pressures in early 1917, as the Imperial German Navy prepared to resume unrestricted submarine warfare on January 31, a policy anticipated to provoke U.S. entry into World War I against the Central Powers.^[21] German military leaders, including Admiral Alfred von Tirpitz and the High Command, calculated that the intensified U-boat campaign could starve Britain into submission within months by severing Allied supply lines, but this risked unleashing America's industrial and manpower reserves—potentially over 4 million troops—onto European battlefields, tipping the balance decisively toward the Entente.^[22] The telegram's proposals aimed to preempt this by forcing the U.S. to divert forces southward and westward, tying down divisions in hemispheric defenses and preventing reinforcements to France and Britain, where German resources were already stretched thin by the Allied blockade and two-front attrition. The overture to Mexico leveraged long-standing territorial grievances from the 1846–1848 Mexican-American War, in which Mexico ceded Texas, New Mexico, and Arizona—comprising over 500,000 square miles—under the Treaty of Guadalupe Hidalgo, fueling revanchist sentiments among some Mexican elites despite the nation's post-revolutionary disarray.^[23] Under President Venustiano Carranza, Mexico grappled with factional violence, economic collapse, and ineffective governance following the 1910–1920 revolution, rendering it militarily incapable of sustained aggression against the U.S.; nonetheless, German Foreign Secretary Arthur Zimmermann viewed financial subsidies and territorial incentives as sufficient to incite border raids or proxy disruptions, exploiting U.S. vulnerabilities along a 2,000-mile frontier without requiring full Mexican mobilization.^[24] This calculus reflected a first-principles assessment of asymmetric leverage: even limited Mexican involvement could compel American logistical reallocations, buying Germany time amid its own munitions shortages and manpower deficits exceeding 1 million by late 1916.^[3] Inclusion of Japan in the proposed alliance disregarded its 1902 Anglo-Japanese Alliance and 1914 commitments to the Entente, banking instead on Tokyo's imperial expansionism in the Pacific and Asia—evident in its seizure of German Tsingtao in 1914 and Twenty-One Demands on China in 1915—to lure defection with vague promises of U.S. Pacific territories.^[24] Zimmermann later justified this in a March 29, 1917, Reichstag address, arguing that allying with distant powers was essential given Germany's encirclement by "a superior world of enemies," though Japan's entrenched economic ties to Britain and focus on Siberian interventions post-1917 Brusilov Offensive rendered the gambit a profound misjudgment born of resource-driven desperation rather than realistic diplomacy.^[25] Such proposals underscored broader German strategic errors, prioritizing high-risk intrigue over consolidated European defenses amid dwindling coal reserves and food rations that had already sparked the 1916–1917 Turnip Winter famine.^[22]

Detailed Content and Proposals

The Zimmermann Telegram, dispatched on January 16, 1917, by German Foreign Secretary Arthur Zimmermann to German Minister Heinrich von Eckardt in Mexico City, proposed a military alliance between Germany and Mexico in the event that the United States declared war on Germany following the resumption of unrestricted submarine warfare.^[1]^[2] The decoded message explicitly stated: "We intend to begin on the first of February unrestricted submarine warfare and to stop the diplomacy of peace in order to carry on the war with all possible means. We shall endeavor to keep the United States of America neutral. In case of this hope of neutrality not being fulfilled...we make Mexico a proposal of alliance on the following basis: conduct war jointly, make peace jointly, generous financial support and an agreement by us that Mexico is to reconquer the lost territory in New Mexico, Texas, and Arizona. The territory is to be settled later by settlement between us and Japan. Mediation by us is to be asked for obtaining this goal. The proposal is to be transmitted in the most confidential manner."^[1]^[26] The core proposals included German financial backing for Mexican military operations against the United States, restitution of territories ceded to the U.S. in the 1848 Treaty of Guadalupe Hidalgo—specifically Texas, New Mexico, and Arizona—and diplomatic efforts to involve Japan in a coordinated assault on American Pacific possessions, with territorial adjustments to be negotiated post-victory.^[1]^[3] Encoded initially in the German Foreign Ministry's 13040 cipher for transmission to Washington before retransmission in the 0075 cipher to Mexico, the telegram conditioned activation of the alliance on U.S. belligerence, underscoring its role as a contingency plan tied to Germany's strategic pivot to total submarine warfare.^[3]^[24] These offers reflected profound German overreach, as Berlin possessed no viable means to project substantial military force across the Atlantic to bolster Mexican efforts, given its depleted surface fleet and commitment to European fronts and U-boat operations.^[3] Mexico's armed forces, numbering approximately 70,000-100,000 ill-equipped personnel amid internal instability, faced insurmountable disparities against U.S. industrial capacity—evidenced by America's 1916 steel production exceeding 50 million tons annually versus Mexico's negligible output—and a potential mobilization of over 4 million troops, rendering territorial reconquest logistically infeasible without direct German intervention that geography and naval realities precluded.^[27] The absence of enforceable mechanisms for financial aid delivery or post-war territorial guarantees further highlighted the scheme's detachment from operational constraints, prioritizing desperation over pragmatic assessment.^[27]

Encoding, Routing, and Vulnerabilities

The Zimmermann Telegram was initially transmitted from the German Foreign Office in Berlin to the German ambassador in Washington, D.C., Count Johann Heinrich von Bernstorff, on January 16, 1917, using diplomatic code 0075—a relatively new "lottery" cipher introduced in mid-1916—over U.S. State Department cables, which Germany relied upon as a neutral channel after its own transatlantic cables had been severed at the war's outset.^[24]^[3] Bernstorff then re-encoded the message in the older diplomatic code 13040, in use since 1912, and forwarded it to German Minister Heinrich von Eckardt in Mexico City via commercial telegraph lines, routing through the German legation in Stockholm and the Swedish "round-the-world" cable system to circumvent direct U.S.-monitored paths, with the message arriving on January 19.^[3]^[28] This dual encoding and rerouting reflected operational insecurities, as direct transmission to Mexico via U.S. cables had been deemed risky amid eroding American neutrality, yet the chosen commercial and neutral-legation paths remained vulnerable to international cable tapping by British intelligence, which controlled key Atlantic links.^[24]^[3] Code 13040, stored insecurely in the Washington embassy's poorly secured cabinet accessible to multiple officials, had been compromised years earlier through British recovery of German code materials, rendering the retransmission exposed despite German assumptions of security.^[3] Similarly, code 0075, while newer, fell to British cryptanalytic efforts aided by prior naval codebook captures.^[3] Zimmermann's directive for written confirmation of receipt compounded these lapses, prompting Eckardt to reply via analogous insecure channels, with verification communications extending exposure risks into February and necessitating multiple handling points that amplified interception opportunities.^[28] The retransmission delays—from Washington's re-encoding to the circuitous Swedish routing—further prolonged the message's transit over monitored lines, highlighting German diplomatic overreliance on outdated codes and neutral conduits without adequate safeguards like couriers or fresh encipherment.^[3]

Interception and Decryption

British Room 40 Operations

Room 40, the Admiralty's cryptanalytic section, was established in October 1914 under the leadership of Sir Alfred Ewing, following the recovery of German naval codebooks from the cruiser SMS Magdeburg, which ran aground off Estonia on August 26, 1914, with Russian forces salvaging the materials and sharing them with Britain.^[29] This windfall provided the Signalbuch der Kaiserlichen Marine (SKM), enabling initial breaks into German naval signaling.^[30] Housed in Room 40 of the Old Admiralty Building in London, the unit expanded rapidly under Director of Naval Intelligence Reginald Hall, employing academics, linguists, and chess masters to handle code recovery and traffic analysis.^[31] The section's operations centered on intercepting and exploiting German wireless and cable traffic, leveraging Britain's dominance over global telegraph networks after severing five direct German cables on August 5, 1914, forcing Berlin to route diplomatic and naval messages through neutral countries like Sweden, Denmark, and the United States.^[24] Routine surveillance included tapping transatlantic lines and monitoring relay stations, such as the German wireless facility at Sayville, Long Island, which retransmitted signals from Nauen, Germany, to the Western Hemisphere.^[28] By late 1914, Room 40 had achieved early successes, such as decoding signals that revealed German light cruiser maneuvers and High Seas Fleet dispositions during the Hartlepool raid on December 16, 1914, allowing British forces to track and counter threats effectively.^[32] This established intelligence framework extended to diplomatic traffic, where Room 40 maintained access to German Foreign Office codes through captured merchant vessel books and incremental recoveries, positioning the unit to routinely process high-level intercepts without alerting adversaries to compromises.^[30] The Zimmermann Telegram's interception on January 16, 1917, exemplified this dominance, as operators captured the message via the Swedish-U.S. cable roundabout and Sayville relay, integrating it into ongoing monitoring of Berlin's overtures to neutrals amid unrestricted submarine warfare preparations.^[28] Such efforts underscored Room 40's role in sustaining Britain's strategic edge through persistent signals intelligence rather than isolated feats.^[31]

Technical Decryption Methods

The Zimmermann Telegram was encoded using German Foreign Office Code No. 13040, a numerical substitution cipher where phrases were replaced by five-digit groups from a codebook, which had been partially recovered by British cryptanalysts through earlier captures of German materials and interceptions of diplomatic traffic.^[3] This code's reuse provided Room 40 with a significant advantage, as prior work had reconstructed substantial portions, allowing rapid identification of groups via frequency analysis and cribs—expected plaintext phrases such as standard salutations or confidentiality markers common in German diplomacy.^[3] ^[33] Nigel de Grey and William Montgomery, key cryptographers in Room 40, initiated decryption immediately after the telegram's interception on January 16–17, 1917, leveraging these cribs to break initial segments despite the message's superencipherment, which involved additive transposition or key-based obfuscation over the base code to enhance security.^[34] ^[35] Partial decryption emerged within days, revealing core intent by late January, while full recovery of the 13040-encoded text, cross-referenced against a variant in the newer but also compromised Code 0075, was achieved by early February 1917.^[3] ^[36] To verify the decode without exposing interception sources, Room 40 cross-checked against a parallel transmission relayed through neutral Swedish diplomatic channels, which matched the decrypted content and confirmed authenticity amid superencipherment challenges.^[3] The Germans' failure to introduce fresh codes or robust superencipherment—relying instead on outdated diplomatic systems vulnerable to crib-based attacks—stemmed from overconfidence in cable security and resource constraints during wartime.^[3] British authorities deliberately withheld detailed cryptanalytic techniques upon revelation to the United States, prioritizing preservation of Room 40's edge over German naval and military codes, which remained unbroken and vital for ongoing U-boat tracking; instead, a cover story attributed the acquisition to a Mexican foreign office leak, trading methodological transparency for strategic secrecy.^[3] This approach reflected causal trade-offs in signals intelligence, where exposing codebreaking prowess risked prompting German cipher reforms that could blind Allied operations more severely than the diplomatic breach.^[3]

Revelation and Verification

Transfer to US Authorities

On 19 February 1917, Admiral Sir William Hall, head of Britain's Room 40 naval intelligence unit, disclosed the decrypted Zimmermann Telegram to Edward N. Bell, counselor at the US Embassy in London.^[37] To conceal the fact that British cryptanalysts had intercepted and broken German diplomatic codes transmitted via neutral US undersea cables, Hall presented a fabricated cover story attributing the document's acquisition to sources within the Mexican telegraph system.^[38] This deception involved fabricating a narrative that a copy had been obtained from the German legation in Mexico City through a local employee at the telegraph office, thereby avoiding revelation of Britain's ongoing codebreaking operations against Germany.^[3] Bell immediately shared the intelligence with US Ambassador Walter Hines Page, who on 24 February 1917 forwarded a clean, typed transcription of the decode—stripped of any British analytical annotations or "fingerprints"—to Secretary of State Robert Lansing via diplomatic channels.^[26] This version preserved the telegram's content while maintaining the Mexican provenance ruse, ensuring the US government could verify its authenticity independently without suspecting the true intercept method.^[24] Britain's decision to transfer the telegram reflected a calculated risk-reward assessment: by alerting the US to Germany's provocative overture, London sought to erode American neutrality and accelerate entry into the war on the Allied side against their mutual adversary, even at the potential cost of compromising valuable cryptographic advantages and straining transatlantic trust in secure communications.^[39] Hall had delayed disclosure until German unrestricted submarine warfare commenced on 1 February, maximizing the document's inflammatory impact amid rising US tensions with Berlin.^[3]

Initial Doubts and Zimmermann's Confirmation

The United States government received the decrypted Zimmermann Telegram from British authorities on February 24, 1917, but initial reactions within the Wilson administration were marked by skepticism regarding its authenticity, stemming from prior experiences with British wartime propaganda efforts.^[24] The 1915 Bryce Report, which alleged widespread German atrocities in Belgium, had been criticized post-war for incorporating unverified and exaggerated accounts to sway neutral opinion, fostering wariness toward unsubstantiated intelligence from London.^[40] Fears persisted that the telegram might represent a similar fabrication designed to provoke American intervention in World War I.^[41] To verify the document independently without compromising British codebreaking sources, U.S. State Department officials monitored German diplomatic activities in Mexico, where reports indicated that Heinrich von Eckardt, the German minister there, had approached Mexican officials with proposals aligning with the telegram's content, including overtures for a potential alliance and territorial incentives.^[21] This empirical confirmation from on-the-ground observations corroborated the message's directives. Additionally, the telegram had been transmitted via multiple routes—using U.S. State Department cables in code 0075 and Swedish diplomatic channels in code 13040—allowing intercepts across distinct encryptions that independently matched, diminishing prospects of a singular forgery.^[42] Skepticism in the American public and Congress lingered after the telegram's publication on March 1, 1917, with widespread doubts about its legitimacy.^[25] These were decisively resolved on March 3, 1917, when Arthur Zimmermann, during a press conference with an American correspondent, affirmed the document's authenticity by declaring, "I cannot deny it. It is true."^[21] Later that day, in a speech to the Reichstag, Zimmermann defended the telegram as a defensive contingency amid Germany's unrestricted submarine warfare policy, admitting its proposal to Mexico as a strategic precaution should the United States enter the war against Germany.^[25] This public concession, coupled with the absence of any credible evidence for Allied manipulation despite initial German assertions of forgery, established the telegram's veracity through direct authorial acknowledgment and cross-verified intelligence.^[3]

Reactions

US Government and Public Response

The Zimmermann Telegram's contents were released to the American public on March 1, 1917, through front-page stories in major newspapers, including The New York Times reporting under the headline "Washington Exposes Plot," detailing the German Foreign Ministry's proposal for a Mexican alliance against the United States.^[43] This disclosure ignited immediate and intense public outrage, with editorials nationwide portraying the scheme as an aggressive violation of U.S. neutrality and a plot to dismember American territory, shifting sentiment from prior isolationist hesitancy toward demands for retaliation.^[21]^[4] Mass rallies erupted in urban centers like New York City and Boston, where crowds numbering in the thousands gathered to denounce Germany, often waving flags and calling for military preparedness.^[44] The revelation eroded opposition even among German-American communities, many of whom viewed the proposal's territorial ambitions—targeting U.S. states like Texas and New Mexico—as incompatible with their loyalty to the adopted nation, leading to public repudiations and increased enlistments from immigrant groups.^[23] Public opinion polls and newspaper correspondence from the period reflected a sharp uptick in war support, with isolationist voices marginalized as the telegram underscored German duplicity amid ongoing submarine attacks on U.S. shipping.^[45] In response, President Woodrow Wilson incorporated the telegram into his April 2, 1917, address to a joint session of Congress, citing it as "eloquent evidence" of Germany's intent to "stir up enemies against us at our very doors" alongside unrestricted submarine warfare, framing war as essential for national defense and global democracy.^[46]^[47] Congress approved Wilson's war request on April 6, 1917, with the House voting 373–50 and the Senate 82–6, demonstrating broad bipartisan consensus driven by the telegram's exposure of belligerent designs.^[8]^[48] The government's swift verification, including Zimmermann's own admission on March 3, 1917, further solidified resolve, prompting accelerated mobilization efforts.^[21]

Mexican Evaluation and Rejection

Upon receiving the German proposal via Minister Heinrich von Eckardt in late January 1917, President Venustiano Carranza instructed a joint military and civilian commission to assess its feasibility.^[24] The commission concluded that allying with Germany for an invasion of the United States was logistically impossible, citing Mexico's ongoing civil strife during the Mexican Revolution (1910–1920), which had depleted its military resources and left its government unstable.^[49] Carranza's advisors highlighted the insurmountable power imbalance, including the United States' superior industrial capacity, larger standing army, and geographical proximity, which would enable rapid mobilization against any Mexican incursion.^[50] Financial incentives in the proposal—such as German subsidies for war costs and recovery of pre-1848 territories like Texas, New Mexico, and Arizona—held superficial appeal amid Mexico's economic turmoil, but were dismissed as unrealistic given Germany's inability to deliver promised armaments across the Atlantic amid British naval blockade.^[26] Internal deliberations emphasized that success against the U.S. was unattainable without massive external support, which submarine warfare disruptions rendered improbable.^[24] This pragmatic assessment reflected Mexico's recognition of causal realities: its weakened state precluded revanchist adventures, contrary to German Foreign Secretary Arthur Zimmermann's overestimation of latent territorial grievances as a motivator for aggression.^[49] On April 14, 1917—one week after the U.S. declaration of war on Germany—Carranza issued an official reply to Berlin rejecting the alliance, stating that Mexico had no interest in pursuing it to avoid further provocation of its northern neighbor.^[26] The response underscored the proposal's detachment from Mexico's strategic constraints, prioritizing neutrality and internal consolidation over a doomed offensive pact.^[24]

Japanese Disavowal

The Zimmermann Telegram instructed the German ambassador in Mexico to propose that, in the event of war between Germany and the United States, Mexico should ally with Germany and invite Japan to join the conflict against the U.S., with Germany promising financial support and territorial concessions to both nations.^[24] This element aimed to exploit Japan's imperial ambitions in the Pacific while drawing it away from its existing commitments.^[3] Following the public revelation of the telegram on March 1, 1917, Japanese Prime Minister Terauchi Masatake's cabinet issued a formal denial on March 3, 1917, stating that no such proposal had been received from Germany or Mexico and expressing that Japan would reject any overture of this nature as repugnant to its national honor and incompatible with its obligations under the Anglo-Japanese Alliance of 1902, which had been renewed in 1905 and 1911 and bound Japan to Britain as an Entente power.^[24]^[51] Terauchi emphasized Japan's loyalty to its allies, noting that participation in an anti-U.S. alliance would betray these ties and undermine Japan's position in World War I, where it had already seized German territories in Asia and the Pacific since declaring war on Germany in August 1914.^[52] Historians have found no archival evidence of secret German-Japanese negotiations prompted by the telegram, aligning with Japan's strategic prioritization of maintaining the Anglo-Japanese Alliance to secure British naval support against potential Russian threats and to consolidate gains in China and Siberia, rather than risking entanglement in a distant American conflict.^[24]^[51] The disavowal reinforced Japan's alignment with the Allies, countering any German hopes of inducing defection amid its own deteriorating position on the Western Front.^[52]

German Domestic and Diplomatic Fallout

Arthur Zimmermann admitted the telegram's authenticity to the German press on March 3, 1917, framing it as a defensive contingency measure intended solely if the United States declared war on Germany, with the aim of engaging American forces on their southern border to safeguard German interests in Europe.^[25] This defense portrayed the proposal as pragmatic realpolitik rather than unprovoked aggression, yet it failed to mitigate the damage to Germany's international standing, as the overt territorial incentives to Mexico—promising recovery of lost provinces like Texas, New Mexico, and Arizona—reinforced views of German diplomacy as opportunistic and imperialistic among neutral observers in Europe and Latin America.^[22] Domestically, the revelation elicited limited public backlash due to strict wartime censorship and government control over media narratives, which emphasized the telegram's strategic intent without acknowledging its interception or the breach of secrecy. However, it eroded confidence in Zimmermann's leadership among military and political elites, who saw the exposure as a self-inflicted wound that needlessly antagonized potential mediators and accelerated the shift of U.S. public opinion toward intervention. The affair compounded frustrations from the concurrent resumption of unrestricted submarine warfare on February 1, 1917, which had already strained diplomatic relations.^[23] Zimmermann tendered his resignation as State Secretary for Foreign Affairs on August 22, 1917, officially citing health reasons but amid mounting criticism over diplomatic missteps, including the telegram's fallout and the failure of U-boat operations to compel British capitulation before American mobilization. His departure marked a symbolic acknowledgment of policy reversals that isolated Germany further, as subsequent foreign ministers struggled to counter the propaganda narrative of German perfidy. The heightened U.S. animosity fueled expedited economic sanctions, including tightened Allied naval blockades that intensified resource shortages in Germany by late 1917, contributing to domestic economic strain without offsetting military gains.^[53]

Impact

Acceleration of US War Entry

The resumption of German unrestricted submarine warfare on February 1, 1917, intensified maritime threats to neutral American shipping, with U-boats sinking multiple U.S. merchant vessels in the ensuing weeks, including the Lyman M. Law on February 22 and the California on February 26, contributing to mounting pressure for defensive measures such as the arming of American merchant ships authorized by Congress on March 9.^[8] These attacks eroded U.S. neutrality but lacked a singular provocative element to unify opinion; the interception and public disclosure of the Zimmermann Telegram on March 1 supplied that catalyst by revealing Germany's overtures to Mexico for an alliance against the United States, including territorial incentives for Texas, New Mexico, and Arizona.^[1] This intelligence, verified through Zimmermann's own admission on March 3, framed Germany not merely as a maritime aggressor but as a conspiratorial power intent on hemispheric subversion, thereby accelerating the shift from preparedness debates to war advocacy.^[21] Prior U.S. economic alignments had already tilted toward the Allies, with private banks extending over $2 billion in credits and loans by early 1917—contrasted with negligible German financing—while American firms supplied munitions and goods unhindered by any formal embargo, fostering interdependence that submarine losses now imperiled.^[9] The telegram's proximate effect was to merge these submarine-induced economic perils with a perceived existential intrigue, enabling President Wilson to request war on April 2 by invoking both the "warfare against mankind" of U-boats and the "eloquent proof" of the Zimmermann dispatch as evidence of German duplicity.^[47] Congress responded swiftly, declaring war on April 6, with contemporaneous newspaper editorials and congressional records attesting to the telegram's role in galvanizing support amid the submarine crisis, though isolationist holdouts persisted until this dual impetus overwhelmed them.^[4]

Immediate Military and Diplomatic Shifts

The United States, upon declaring war on Germany on April 6, 1917, promptly mobilized its naval assets to support Allied anti-submarine efforts, including the adoption of convoy protections for transatlantic shipping. In early June 1917, the U.S. Navy contributed destroyers and auxiliaries to inaugurate regular ocean convoys from North American ports, marking the system's full operationalization and integrating American forces into Royal Navy-led operations. This coordination reduced merchant vessel sinkings from a peak of approximately 870,000 tons in April 1917 to under 300,000 tons monthly by late 1917, with convoyed ships experiencing losses below 2 percent overall.^[54]^[55] Diplomatically, the telegram's exposure intensified Germany's isolation among neutrals, as Mexico—after evaluating the proposal—affirmed its neutrality and declined alliance with Berlin, citing impracticality and lack of resources. This rejection preserved Mexico's non-belligerent status despite prior U.S.-Mexico border frictions from revolutionary incursions, easing American apprehensions of a southern front and enabling undivided focus on European deployments. Allied coordination strengthened accordingly, with enhanced intelligence sharing on German naval movements.^[8] The revelation underscored compromises in German diplomatic codes, which British intelligence had exploited via intercepts like Code 13040 and 0075; Germany, suspecting treason over cryptanalytic breach, initiated internal purges and cautiously shifted to alternative transmission routes, including couriers, for sensitive dispatches in the ensuing months. Declassified records confirm continued Allied access to some channels but note German adaptations that complicated subsequent monitoring.^[3]

Long-Term Geopolitical Ramifications

The interception and publication of the Zimmermann Telegram decisively contributed to United States entry into World War I on April 6, 1917, enabling the deployment of approximately 2 million American Expeditionary Forces troops to Europe by late 1918, which accelerated the Allied collapse of German forces and prompted the Armistice of November 11, 1918.^[1]^[56] This influx of fresh U.S. manpower shifted the war's momentum, preventing a prolonged stalemate that might have forced negotiated terms more favorable to Germany, but it also positioned the United States as a pivotal actor at the Paris Peace Conference of 1919.^[21] U.S. participation, catalyzed in part by the telegram's exposure of German duplicity, facilitated President Woodrow Wilson's influence on the Treaty of Versailles signed June 28, 1919, whose Article 231 "war guilt" clause and demands for German disarmament, territorial cessions (including Alsace-Lorraine to France and parts of Prussia to Poland), and reparations exceeding 132 billion gold marks engendered profound national humiliation and economic distress in Germany.^[1]^[57] These punitive measures, unmitigated by U.S. troop presence signaling overwhelming Allied superiority, cultivated revanchist ideologies that undermined the Weimar Republic and contributed to the political radicalization culminating in Adolf Hitler's ascent by 1933.^[57] The episode established a precedent for signals intelligence's role in shaping diplomatic outcomes, as British Room 40's decryption demonstrated codebreaking's capacity to alter alliances without direct military engagement, influencing subsequent interwar and World War II practices in protecting sources while leveraging intercepts for policy.^[58]^[21] Concurrently, the telegram's proposed Mexico-Japan axis failed to materialize, with Mexico securing no territorial recoveries in Texas, New Mexico, or Arizona, and Japan—having disavowed involvement—proceeding to annex German Pacific holdings and Shandong Peninsula concessions under Versailles, unhindered by the aborted scheme and setting the stage for its 1930s aggressions in Manchuria and beyond.^[26]^[51]

Historical Analysis and Legacy

Scholarly Debates on Causal Role

Barbara Tuchman's 1958 monograph The Zimmermann Telegram depicted the message as a catastrophic German diplomatic error that decisively shifted U.S. public sentiment and eroded President Woodrow Wilson's commitment to neutrality, framing it as the tipping point amid escalating tensions.^[59] However, this narrative has been critiqued in later historiography for overstating the telegram's independent causality, with scholars arguing it functioned primarily as corroborative proof of German belligerence rather than the originating impetus for war. Unrestricted submarine warfare, resumed on January 31, 1917, and resulting in the loss of American lives and vessels—such as the sinking of five U.S. merchant ships between March 16 and 18—served as the dominant catalyst, prompting the diplomatic break on February 3 and arming Wilson with justification for intervention irrespective of the intercepted proposal.^[24]^[8] Thomas Boghardt's 2012 analysis underscores multifaceted drivers, including U.S. economic entanglements with the Allies—totaling over $2.2 billion in loans and credits by early 1917—and cultural affinities, positing that the telegram merely alleviated Wilson's lingering doubts while submarine policy provided the irrefutable casus belli.^[60]^[61] Quantitatively oriented assessments, such as those by Holger Herwig, minimize its decisiveness on the war's trajectory, suggesting U.S. entry hastened Allied success by supplying troops and materiel but would have yielded limited divergence—perhaps less than a year's delay in German collapse—absent the intervention, given Britain's naval dominance and the Central Powers' internal strains.^[62] Authenticity, confirmed by Zimmermann's own March 3, 1917, admission in the Reichstag, overrides early skepticism, though British Room 40's interception and timed disclosure—delayed until after U.S. vessels sank to conceal codebreaking capabilities—invited charges of manipulative orchestration, a factor downplayed in orthodox accounts.^[23]^[63] Revisionist perspectives from the interwar period, notably Harry Elmer Barnes's 1926 essays and Genesis of the World War (1926), recast U.S. involvement as exacerbating a stalemated conflict ripe for negotiated peace, arguing the telegram's propaganda amplification masked profiteering motives and British influence on Wilson, thereby extending carnage that claimed an additional 116,000 American lives without altering core power balances.^[64]^[65] These critiques, drawing on declassified documents revealing Allied financial dependencies, challenge causal attributions privileging the telegram over systemic pressures like Germany's blockade desperation, aligning with causal analyses that prioritize empirical sequences—submarine escalation preceding and outlasting the diplomatic gambit—in evaluating entry's precipitants. Recent works, including Boghardt's integration of intelligence records, reinforce this by evidencing pre-telegram momentum toward belligerence, countering monocausal emphases in popular histories.^[66]^[61]

Artifacts, Autographs, and Enduring Significance

The United States National Archives holds a decode of the Zimmermann Telegram, prepared by Edward Bell of the American Embassy in London and transmitted to the State Department on March 2, 1917, which authenticated the British-intercepted message.^[67] A photostat copy, obtained by the State Department from Western Union records of the telegram as relayed to the German ambassador in Mexico, further verified its contents and origin.^[68] These documents, preserved as primary artifacts, confirm the telegram's transmission via neutral American telegraph lines despite wartime censorship risks.^[68] The original draft, signed by German Foreign Secretary Arthur Zimmermann on January 16, 1917, appears in declassified German official records referenced in post-war analyses, underscoring the message's authenticity from imperial archives.^[28] No surviving autograph of the dispatched version has been publicly confirmed beyond these reproductions, though the event's cryptographic breakthrough—via British Room 40 decryption—highlighted vulnerabilities in diplomatic codes, paralleling later signals intelligence operations in revealing adversarial strategies without direct combat.^[3] In popular depictions, the telegram features in political cartoons exaggerating its explosive diplomatic impact, such as one portraying it detonating in Kaiser Wilhelm II's hands, which amplified public outrage but overstated the intrigue for propagandistic effect.^[38] Its enduring significance lies in illustrating diplomatic hubris through insecure channels, where verifiable intercepts exposed genuine German expansionist aims, informing modern intelligence practices on balancing source protection against strategic disclosure.^[3] This causal demonstration of codebreaking's policy influence persists in cryptologic doctrine, emphasizing empirical validation over speculation in asymmetric conflicts.^[69]

References

[1]
Zimmermann Telegram (1917) | National Archives
Aug 22, 2022 · This telegram, written by German Foreign Secretary Arthur Zimmermann, is a coded message sent to Mexico, proposing a military alliance against the United ...
[2]
Historical Documents - Office of the Historian
Balfour has handed me the text of a cipher telegram from Zimmermann, German Secretary of State for Foreign Affairs, to the German Minister to Mexico, which was ...
[3]
[PDF] The Zimmermann Telegram - National Security Agency
They used the. Mexican cover story, which Page accepted, to explain their acquisition of the telegram, thus hiding their reading of American message traffic.
[4]
The Zimmermann Telegram | National Archives
In January 1917, British cryptographers deciphered a telegram from German Foreign Minister Arthur Zimmermann to the German Minister to Mexico, Heinrich von ...
[5]
1917: Year of stalemate | National Army Museum
1916 witnessed two of the longest and most notorious battles of the First World War. Both resulted in hundreds of thousands of casualties for both the Allies ...
[6]
Attritional Warfare: Stalemate on the Western Front During WWI
Jul 18, 2024 · Until the war's final year, the Entente and Central Powers were locked in a grinding stalemate fought between wide lines of opposing trenches.
[7]
Trench Warfare | National WWI Museum and Memorial
Fighting ground to a stalemate. Over the next four years, both sides would launch attacks against the enemy's trench lines, attacks that resulted in horrific ...
[8]
U.S. Entry into World War I, 1917 - Office of the Historian
German policymakers argued that they could violate the “Sussex pledge” since the United States could no longer be considered a neutral party after supplying ...
[9]
U.S. Economy in World War I – EH.net - Economic History Association
Over four million Americans served in the armed forces, and the US economy turned out a vast supply of raw materials and munitions.
[10]
THE IMPACT OF WORLD WAR I ON AMERICA - jstor
Among the other half, sympathies ran five to one in favor of the Allies, that is, Britain and France. Sympathy for the. Central Powers, principally Germany, was ...<|control11|><|separator|>
[11]
Woodrow Wilson: Campaigns and Elections | Miller Center
The Campaign and Election of 1916. In 1916, President Wilson ... During the convention, the delegates cheered a new campaign slogan, “He Kept Us Out of War ...
[12]
The Lusitania Disaster | Articles & Essays | Newspaper Pictorials
On May 7, 1915, the German submarine (U-boat) U-20 torpedoed and sank the Lusitania, a swift-moving British cruise liner traveling from New York to Liverpool, ...
[13]
Sussex pledge | Date, Definition, Significance, & World War I
Sep 12, 2025 · The Sussex pledge was an agreement by the German government during World War I to stop the indiscriminate sinking of nonmilitary ships.
[14]
U.S. Enters the War | National WWI Museum and Memorial
In November of 1916, President Woodrow Wilson won a close re-election under the slogan “He Kept Us Out of War.” Yet in early 1917 when Russia's internal ...
[15]
The British Naval Blockade Of The First World War
World War 1: The British Naval Blockade of Germany occured between 1914 & 1919. A blockade of enemy ports hoped to cut off supplies from the outside world.Missing: hardships | Show results with:hardships
[16]
The British Blockade During World War I: The Weapon of Deprivation
This operation was the British blockade from 1914-1919 which sought to obstruct Germany's ability to import goods, and thus in the most literal sense starve the ...Missing: shortages hardships
[17]
The British Naval Blockade | History of Western Civilization II
The German Board of Public Health claimed that 763,000 German civilians died from starvation and disease caused by the blockade through December 1918. An ...Missing: hardships | Show results with:hardships
[18]
Unrestricted Submarine Warfare, 1917 – 1918 - Airspace Historian
Jul 5, 2019 · [ix] The new German war leadership under Ludendorff and Hindenburg, as such, made the decision late in 1916 to gamble on the U-boats sinking ...
[19]
Unrestricted U-boat Warfare | National WWI Museum and Memorial
At the dawn of 1917, the German high command forced a return to the policy of unrestricted submarine warfare, engineering the dismissal of opponents of the ...
[20]
Germany resumes unrestricted submarine warfare | February 1, 1917
On February 1, 1917, the lethal threat of the German U-boat submarine raises its head again, as Germany returns to the policy of unrestricted submarine warfare.
[21]
Zimmermann Telegram | National WWI Museum and Memorial
Zimmermann Telegram Decoded. The British decode the intercepted message and discover the German proposal for an alliance with Mexico against the United States.
[22]
The Zimmermann Telegram - Army University Press
The Zimmermann Telegram was sent in January 1917 from German Foreign Minister Arthur Zimmermann to Heinrich von Eckardt, the German ambassador to Mexico.
[23]
The Zimmermann Telegram and American Entry into World War I
The Zimmermann telegram painted a future for people from Texas to California of invasion, the loss of their land, and conquest by the soldiers of Mexico and ...
[24]
The Zimmermann Telegram - National Archives
Acting on a coded message intercepted by the men of Room 40, on September 1, 1915, British soldiers boarded a ship near Falmouth, England, and apprehended ...
[25]
[PDF] Arthur Zimmermann's Speech Regarding the Zimmermann Telegram
When I thought of this alliance with Mexico and Japan I allowed myself to be guided by the consideration that our brave troops already have to fight against a ...<|control11|><|separator|>
[26]
The Zimmermann Telegram - Teaching American History
A cipher telegram from Zimmermann, German Secretary of State for Foreign Affairs, to the German Minister to Mexico, which was sent via Washington and relayed ...
[27]
TWE Remembers: The Zimmermann Telegram
Mar 1, 2011 · Zimmermann sent his telegram in mid-January 1917. The message ran fewer than 175 words and was breathtakingly simple—Mexico would get the lands ...<|separator|>
[28]
[PDF] THE ZIMMERMANN TELEGRAM OF JANUARY 16, 1917 AND ITS ...
Nov 16, 2024 · ... communications. As to the routes really used for the transmission ot the Zimmermann telegram, all the evi- dence thus tar cited indicates ...
[29]
The Wreck of the Magdeburg - HistoryNet
Jun 7, 2018 · ... Alfred Ewing, an engineer who had long been interested in ciphers. ... The British intercepted the message, and Room 40 deciphered it. The ...
[30]
Room 40 : Cryptanalysis during World War I - Navy General Board
Sep 17, 2018 · CAPTURE OF THE SECOND CODEBOOK. In 1914 the German lead ship of her class, the light cruiser SMS Magdeburg was deployed into the Baltic, where ...Missing: formation | Show results with:formation
[31]
[PDF] ROOM 40: British Naval Intelligence 1914-18
Acknowledgements. 1 Splinters are Bound to Fly. 1. 2 Room 40 is Born. 8. 3 Codes and Ciphers. 21. 4 A Clear Case of Genius. 34. 5 The First Fruits.
[32]
Room 40 Part 1 - Naval Gazing
May 15, 2022 · Changing a codebook would be a lot of work. Even leaving aside the distribution challenges, this is the early 1900s, so you're having to do everything by hand.Missing: SMS | Show results with:SMS
[33]
The Zimmermann telegram and Room 40 - History of government
Jan 16, 2017 · Unbeknown to Germany, British Naval Intelligence had intercepted the telegram and deciphered it. Whilst the British authorities wanted to ...
[34]
The Zimmermann Telegram Revisited: A Reconciliation of the ...
It was indeed Room 40's normal practice (Figures 2 and 3 ) to write decodes direct into telegrams, but the Bell/de Grey decoding on 2 March was recorded on ...
[35]
How were codes in WW1 reciphered (to enhance security levels ...
Mar 2, 2020 · "The Zimmermann Telegram was superenciphered (encoded again by using the German Diplomatic Code Book, Code No. 13040)." Under "VB codebook" in ...
[36]
A history of British SIGINT (#1); the origins, 1850-1918
Jan 31, 2025 · ... decoding of the infamous Zimmermann telegram. This act, which ... By February, de Grey and Montgomery managed to decrypt the message ...<|separator|>
[37]
World War I: Zimmerman Telegram - ThoughtCo
Apr 3, 2019 · On February 19, 1917, Admiral Sir William Hall, the head of Room 40, presented a copy of the telegram to the secretary of the U.S. Embassy ...
[38]
The Secret History of the Zimmermann Telegram
Mar 1, 2017 · In January 1917, German foreign secretary Arthur Zimmermann dispatched a secret letter to Heinrich von Eckardt, the German minister to Mexico.Missing: context | Show results with:context
[39]
ROOM 40: British Naval Intelligence and the Zimmermann Telegram
The Zimmerman telegram appears to be the evidence needed to bring the United States into the war and save the beleaguered Allies. Select your course of action. ...
[40]
The Historian Who Sold Out - History News Network
But even these latter day scholars admit Bryce's report was seriously "contaminated" by the rapes, amputations and speared babies. They blamed this lapse on ...
[41]
President Wilson Learns of the Zimmerman Telegram
Feb 26, 1997 · Official fears at the White House and the State Department that the Congress and the American people would not believe the authenticity of the ...Missing: initial doubts
[42]
The Zimmermann Telegram at the National Cryptologic ... - Virmuze
Oct 27, 2020 · On January 16, 1917, the Imperial German foreign minister, Arthur Zimmermann, sent a coded telegram to the German ambassador in Washington, D.C. ...
[43]
Our Government Has Zimmermann's Note of ... - The New York Times
March 1, 1917. WASHINGTON EXPOSES PLOT; Our Government Has Zimmermann's Note of Jan. 19. BIG PROMISES. Credit...The New York Times Archives. See the article in ...
[44]
America Outraged by Zimmermann Telegram - Mental Floss
Mar 7, 2017 · Fortunately for the Allies, British intelligence held a trump card in the form of the Zimmermann Telegram, containing Germany's sensational ...Missing: transfer | Show results with:transfer
[45]
Introduction - Zimmermann Telegram: Topics in Chronicling America
Jun 12, 2025 · The information in this guide focuses on primary source materials found in the digitized historic newspapers from the digital collection ...
[46]
The World Must Be Made Safe for Democracy
Wilson recounted the history of deteriorating relations with Germany in his war address but gave the nation other reasons to fight besides self-defense. Using ...
[47]
Wilson's war message to Congress -- April 2, 1917 - Khan Academy
That it means to stir up enemies against us at our very doors the intercepted Zimmermann note to the German Minister at Mexico City is eloquent evidence. We ...Missing: Telegram | Show results with:Telegram<|separator|>
[48]
Joint Address to Congress Leading to a Declaration of War Against ...
Apr 4, 2025 · ... the slogan “He kept us out of war,” reluctantly concluded that war was inevitable. In his speech before a special session of Congress, Wilson ...
[49]
Zimmermann Telegram - 1914-1918 Online
Oct 8, 2014 · In that case, Germany wanted to generously support the Mexicans and offer them Texas, New Mexico, and Arizona as war booty. Japan was to be ...
[50]
https://nationalinterest.org/blog/buzz/zimmerman-telegram-germanys-last-ditch-effort-have-mexico-fight-america-109251
[51]
Japan's Reaction to the Zimmermann Telegram, March 1917
Japan denied any sympathy for German anti-US efforts, stated no discussions occurred, and would refuse any such proposal, as it would be repugnant to their ...
[52]
[PDF] Japanese-Response-to-Zimmerman-Telegram.pdf
Terauchi stated the proposal was repugnant to Japan's honor, that they would not betray allies, and that the proposal was not communicated to the Japanese ...
[53]
How one telegram helped to lead America toward war
Feb 26, 2024 · The Zimmermann Telegram was a message sent on January 12, 1917, from the German foreign minister Arthur Zimmerman to the country's embassy in Washington, DC.
[54]
The First U.S. Overseas Troop Convoy
Sep 10, 2019 · The arrival of the first convoy carrying the soldiers and Marines of the American Expeditionary Force at Saint-Nazaire, France, on 26 June 1917 ...Missing: integration | Show results with:integration
[55]
Protecting Allied Ships during WWI: The Convoy System Comes to ...
Aug 17, 2017 · In early June, the First Sea Lord Admiral John Jellicoe specifically requested more American anti-submarine ships for patrols around Europe. ...Missing: integration | Show results with:integration
[56]
United States of America and the First World War
By the fall of 1918, half of the 2 million American troops overseas were deployed to the front lines. The Americans' high combat casualty rates reflected ...
[57]
How the Treaty of Versailles and German Guilt Led to World War II
Jun 29, 2018 · The Versailles Treaty forced Germany to give up territory to Belgium, Czechoslovakia and Poland, return Alsace and Lorraine to France and cede ...
[58]
Real World Impact: How GCHQ's predecessors contributed to...
The 'Zimmermann Telegram' of 1917 demonstrates the need to balance making use of intelligence and protecting its source, which is still relevant today.
[59]
The Zimmermann Telegram by Barbara W. Tuchman
In stock Free deliveryThe Zimmermann telegram was a top-secret message to the president of Mexico, inviting him to join Germany and Japan in an invasion of the United States.Missing: pivotal blunder
[60]
The Zimmermann Telegram | U.S. Naval Institute
Oct 15, 2012 · This book presents the definitive account of the Telegram and questions many traditional views on the origins, cryptanalysis, and impact of the German alliance ...Missing: causal | Show results with:causal<|separator|>
[61]
[PDF] Intelligence, Diplomacy, and America's Entry into World War I - CIA
In his new his- tory, The Zimmermann Telegram, military and intelli- gence historian Thomas Boghardt presents a meticulously researched and well-written ...
[62]
[PDF] <p>Ensuring the Lifeline to Victory: Antisubmarine Warfare, Convoys ...
A good many other Americans, including a large contingent in the press, called for war. Amid the furor over Zimmermann's note, German U-boats sank four.
[63]
Full article: The Zimmermann Telegram: Intelligence, Diplomacy ...
Jan 10, 2020 · The Zimmerman telegram may have removed Woodrow Wilson's personal doubts about intervention, but it was unrestricted submarine warfare that ...Missing: debates causal
[64]
Harry Elmer Barnes
Professor Barnes became convinced by the early publication of previously secret documents and memoirs that a great injustice had been done to Germany.
[65]
Harry Elmer Barnes on the Disastrous Inception and Consequences ...
It was generally believed in 1917 and thereafter that the intervention of the United States in the World War on the side of the Allies saved human civilization.
[66]
What Did It All Mean? The United States and World War I - Cairn
Oct 22, 2014 · Thomas Boghardt, The Zimmermann Telegram: Intelligence, Diplomacy, and America's Entry into World War I (Annapolis, Maryland: Naval Institute ...
[67]
NARA Exhibit: American Originals, Part 2: World War I
Sep 30, 1998 · Decode of the Zimmermann Telegram made by Edward Bell of the American Embassy in London, sent to the State Department, March 2, 1917, ...
[68]
World War I: Photostat of Zimmermann Telegram, as received by the ...
This copy, obtained by the State Department from Western Union, and the decode of the message, served to authenticate the Zimmermann Telegram.<|separator|>
[69]
Center Cryptologic History - National Security Agency
How has cryptology influenced American history? ... In 1917, British decryption of the Zimmermann Telegram helped push the United States into World War I.