Why did the United States abandon neutrality and enter World War I in 1917?
Analyze the causes of World War I, the reasons the United States entered the war in 1917, including unrestricted submarine warfare, the sinking of the Lusitania, and the Zimmermann Telegram, and the American contribution to Allied victory (NGSSS SS.912.A.5, Reporting Category 1).
An EOC-level answer on US entry into World War I for the Florida US History exam: the MAIN causes of the war, American neutrality, unrestricted submarine warfare and the Lusitania, the Zimmermann Telegram, the declaration of war, and the American Expeditionary Force, with worked stimulus questions.
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What this topic is asking
The United States tried to stay out of World War I for nearly three years before joining the Allies in 1917. The NGSSS benchmark SS.912.A.5 wants you to analyze why the war began in Europe, why American neutrality finally collapsed, and how the United States helped win the war. This is a Reporting Category 1 topic the EOC tests with a quotation from Wilson, a cartoon about submarine warfare, or a question about the specific events that ended neutrality.
The causes of the war (MAIN)
American neutrality
When the war began, the United States declared itself neutral, reflecting a long tradition of staying out of European conflicts. Most Americans wanted no part of the fighting, and President Wilson initially urged the nation to be neutral "in thought as well as in action." But neutrality was strained by trade with the Allies and by German actions at sea.
The events that ended neutrality
Three developments turned American opinion against Germany:
- The sinking of the Lusitania (1915), a British passenger liner, killed nearly 1,200 people including 128 Americans, shocking the public.
- Germany's decision in early 1917 to resume unrestricted submarine warfare, threatening all shipping to Britain.
- The Zimmermann Telegram, a secret German message proposing that Mexico attack the United States in exchange for help regaining Texas, New Mexico, and Arizona. Its interception and publication enraged Americans.
The declaration of war and the American contribution
In April 1917, President Woodrow Wilson asked Congress to declare war, framing the cause in idealistic terms: to make the world "safe for democracy." The United States raised a large army through the Selective Service Act (the draft) and sent the American Expeditionary Force (AEF) under General John J. Pershing to France. Fresh American troops and resources reinforced the exhausted Allies and helped force Germany to seek an armistice on November 11, 1918.
Try this
Q1. State the four long-term causes of World War I summed up by MAIN. [2]
- Cue. Militarism, Alliances, Imperialism, and Nationalism (with the assassination of Archduke Franz Ferdinand as the spark).
Q2. Explain two reasons the United States entered World War I in 1917. [2]
- Cue. Any two of: Germany's unrestricted submarine warfare (including the Lusitania); the resumption of submarine warfare in 1917; the Zimmermann Telegram's proposal that Mexico attack the United States.
Exam-style practice questions
Practice questions written in the style of FLDOE exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
FL EOC (US History, style)1 marksIn 1917 a secret message from Germany proposed that Mexico attack the United States in exchange for help regaining Texas, New Mexico, and Arizona. The interception of this message helped push the United States into World War I. This message was theShow worked answer →
A single-select item (Reporting Category 1, SS.912.A.5).
Correct answer: the Zimmermann Telegram, a secret German proposal to Mexico that outraged Americans when it was intercepted and published.
Markers reward identifying the Zimmermann Telegram as a direct cause of US entry. Distractors such as the Treaty of Versailles (the postwar peace) or the Fourteen Points (Wilson's peace plan) come later and are not a cause of entry.
FL EOC (US History, style)1 marksWhich German naval policy did the most to turn American opinion against Germany and toward entering World War I?Show worked answer →
A single-select item (Reporting Category 1, SS.912.A.5).
Correct answer: unrestricted submarine warfare, in which German U-boats sank ships (including passenger and merchant vessels such as the Lusitania) without warning.
Markers reward connecting submarine attacks on civilian and neutral shipping to the collapse of American neutrality. A distractor naming trench warfare or the use of poison gas describes the fighting in Europe, not the cause of US entry.
Related dot points
- Analyze the impact of World War I on the home front, including war mobilization, propaganda, the Espionage and Sedition Acts and limits on civil liberties, Schenck v. United States, and the Great Migration (NGSSS SS.912.A.5, Reporting Category 1).
An EOC-level answer on the World War I home front for the Florida US History exam: war mobilization and propaganda, the Espionage and Sedition Acts and limits on civil liberties, the Schenck v. United States decision, women in the workforce, and the Great Migration, with worked stimulus questions.
- Analyze Wilson's Fourteen Points, the Treaty of Versailles and the League of Nations, the Senate debate and rejection of the treaty, and the return to isolationism after World War I (NGSSS SS.912.A.5, Reporting Category 1).
An EOC-level answer on the Treaty of Versailles for the Florida US History exam: Wilson's Fourteen Points, the terms of the treaty and the League of Nations, the Senate debate over the League and Article X, the role of Henry Cabot Lodge, and the American return to isolationism, with worked stimulus questions.
- Analyze the causes of American imperialism, including economic, military, and ideological motives, the annexation of Hawaii, and foreign policies such as the Open Door, the Roosevelt Corollary, and dollar diplomacy (NGSSS SS.912.A.4, Reporting Category 1).
An EOC-level answer on American imperialism for the Florida US History exam: the economic, military, and ideological causes of overseas expansion, the annexation of Hawaii, the Open Door Policy, the Panama Canal, the Roosevelt Corollary and Big Stick diplomacy, and dollar diplomacy, with worked stimulus questions.
- Analyze the causes and consequences of the Spanish-American War, including yellow journalism, the explosion of the USS Maine, the acquisition of Puerto Rico, Guam, and the Philippines, and the debate between imperialists and anti-imperialists (NGSSS SS.912.A.4, Reporting Category 1).
An EOC-level answer on the Spanish-American War for the Florida US History exam: yellow journalism and the USS Maine, the war with Spain, the acquisition of Puerto Rico, Guam, and the Philippines, the Philippine-American War, and the imperialist versus anti-imperialist debate, with worked stimulus questions.
- Analyze the causes of World War II, including the rise of totalitarian dictators and aggression, the failure of appeasement, and American isolationism and the Neutrality Acts before US entry (NGSSS SS.912.A.6, Reporting Category 2).
An EOC-level answer on the causes of World War II for the Florida US History exam: the rise of totalitarian dictators, fascism and Nazism, aggression in Europe and Asia, the failure of appeasement, and American isolationism and the Neutrality Acts, with worked stimulus questions.
Sources & how we know this
- US History End-of-Course Assessment Test Item Specifications — Florida Department of Education (2013)
- US History Reporting Category Statements — Florida Department of Education (2013)