--- title: "Sinking of the Lusitania — APUSH Definition & Exam Guide" description: "The Lusitania was a British liner torpedoed by a German U-boat in May 1915, killing 128 Americans and pushing U.S. opinion toward war. Key to APUSH Topic 7.5." canonical: "https://fiveable.me/apush/key-terms/sinking-of-the-lusitania" type: "key-term" subject: "AP US History" unit: "Unit 7" --- # Sinking of the Lusitania — APUSH Definition & Exam Guide ## Definition The Sinking of the Lusitania (May 7, 1915) was a German U-boat attack on a British passenger liner that killed 1,198 people, including 128 Americans, turning U.S. public opinion against Germany and starting the chain of events that ended American neutrality in World War I. ## What It Is On May 7, 1915, a German U-boat torpedoed the *Lusitania*, a British ocean liner, off the coast of Ireland. Of the 1,198 people killed, 128 were Americans. Germany argued the ship was fair game because it sailed through a declared war zone (and it was, in fact, carrying munitions), but to most Americans the attack looked like the murder of civilians. The sinking was the most famous result of Germany's policy of **unrestricted submarine warfare**, which meant U-boats attacked ships without warning instead of following the old rules of stopping vessels and letting passengers off first. Here's the part students often get wrong. The Lusitania did NOT bring the U.S. into the war. Wilson responded with diplomatic protests, Germany temporarily backed off submarine attacks, and the U.S. stayed neutral for almost two more years. What the sinking actually did was crack the foundation of [neutrality](/apush/key-terms/neutrality "fv-autolink"). It made Germany look like the villain in American eyes, fueled pro-Allied [propaganda](/apush/key-terms/propaganda "fv-autolink"), and set the precedent that when Germany resumed unrestricted submarine warfare in early 1917, Wilson treated it as a deal-breaker. ## Why It Matters This term lives in **Topic 7.5 (World War I)** in [Unit 7](/apush/unit-7 "fv-autolink") and supports learning objective **[APUSH](/apush "fv-autolink") 7.5.A**, which asks you to explain the causes and consequences of U.S. involvement in World War I. The CED's essential knowledge (KC-7.3.II) frames U.S. entry as a departure from the long tradition of staying out of European affairs, justified by Wilson's defense of humanitarian and democratic principles. The Lusitania is your best evidence for *how* that shift happened. It's the moment neutrality stopped feeling morally neutral. Dead American civilians made German submarine warfare a humanitarian issue, which is exactly the framing Wilson used in 1917 when he asked Congress to make the world 'safe for democracy.' If you're writing about why the U.S. abandoned isolation, the Lusitania is step one in the cause chain. ## Connections ### Unrestricted Submarine Warfare (Unit 7) The Lusitania is the most famous casualty of this policy. Germany suspended unrestricted submarine warfare after the American outcry in 1915, then resumed it in January 1917. That resumption, not the Lusitania itself, was the immediate trigger for U.S. entry. ### [Zimmermann Telegram (Unit 7)](/apush/key-terms/zimmermann-telegram) Think of the Lusitania (1915) and the [Zimmermann Telegram](/apush/key-terms/zimmermann-telegram "fv-autolink") (1917) as the one-two punch that ended neutrality. The Lusitania built years of anti-German resentment; the telegram, in which Germany proposed an alliance with Mexico against the U.S., converted that resentment into a declaration of war. Exam questions love asking how these two events worked *together*. ### [Propaganda (Unit 7)](/apush/key-terms/propaganda) The sinking handed pro-war propagandists their best material. Images of drowned civilians fed recruitment campaigns, and once the U.S. entered the war in 1917, the Committee on Public Information and posters like Flagg's 'I Want You' built on the anti-German sentiment the Lusitania had planted. ### U.S. Foreign Policy Tradition of Noninvolvement (Units 3, 7, 8) This is a great continuity-and-change thread across periods. [Washington's Farewell Address](/apush/key-terms/washingtons-farewell-address "fv-autolink") warned against entangling alliances, and the U.S. mostly followed that advice for over a century. The Lusitania begins the unraveling of that tradition, and you can trace the thread forward to the Senate rejecting the Treaty of Versailles and to interwar isolationism before WWII. ## On the AP Exam On multiple choice, the Lusitania usually shows up inside a causation question about U.S. entry into WWI. A typical stem asks how the sinking of the Lusitania (1915) and the Zimmermann Telegram (1917) *together* contributed to American involvement, so you need the sequence, not just the event. Other questions use it as background for 1917 recruitment efforts and wartime propaganda. The key skill is precision about causation. The Lusitania shifted public opinion and eroded neutrality, but the proximate causes of the April 1917 declaration of war were Germany's resumption of unrestricted submarine warfare and the Zimmermann Telegram. No released FRQ has used the term verbatim, but it's strong evidence for any essay on APUSH 7.5.A, especially a causation LEQ on why the U.S. abandoned neutrality or a continuity-and-change essay on American foreign policy. ## Sinking of the Lusitania vs Zimmermann Telegram Both pushed the U.S. toward war, but they did different jobs at different times. The Lusitania (May 1915) was a long-term cause that turned public opinion against Germany while the U.S. stayed officially neutral. The Zimmermann Telegram (January 1917) was an immediate cause, a direct German threat to U.S. territory that arrived right as Germany resumed unrestricted submarine warfare. If a question asks what 'directly' caused U.S. entry, the answer is the 1917 events, not the Lusitania. ## Key Takeaways - On May 7, 1915, a German U-boat sank the British liner Lusitania, killing 1,198 people, including 128 Americans. - The sinking turned American public opinion sharply against Germany, but the U.S. did not enter the war until April 1917, almost two years later. - The attack was a product of Germany's unrestricted submarine warfare policy, which Germany paused after American protests and then resumed in 1917. - On the exam, treat the Lusitania as a long-term cause of U.S. entry and the Zimmermann Telegram plus resumed submarine warfare as the immediate causes. - The Lusitania supports the CED's framing (KC-7.3.II) that the U.S. abandoned its tradition of European noninvolvement in response to Wilson's call to defend humanitarian and democratic principles. ## FAQs ### What was the Sinking of the Lusitania in APUSH? It was the May 7, 1915 torpedoing of a British passenger liner by a German U-boat off Ireland, killing 1,198 people including 128 Americans. In APUSH [Topic 7.5](/apush/unit-7/world-war-i-military-diplomacy/study-guide/4wZDa2Pak8FfrKeucUqt "fv-autolink"), it's a major long-term cause of U.S. entry into World War I. ### Did the sinking of the Lusitania cause the U.S. to enter WWI? No, not directly. The U.S. stayed neutral for nearly two more years after the sinking. It entered the war in April 1917 after Germany resumed unrestricted submarine warfare and the Zimmermann Telegram was revealed. The Lusitania's role was shifting public opinion against Germany. ### How is the Lusitania different from the Zimmermann Telegram? The Lusitania (1915) was an attack that killed American civilians and built anti-German sentiment over time. The Zimmermann Telegram (1917) was an intercepted message proposing a German-Mexican alliance against the U.S., and it was an immediate trigger for war. Exam questions often ask how the two worked together. ### Why did Germany sink the Lusitania? Germany had declared the waters around Britain a war zone and practiced unrestricted submarine warfare, attacking ships without warning. The Lusitania was also carrying munitions, which Germany used to justify the attack, though Americans saw it as an assault on civilians. ### How many Americans died on the Lusitania? 128 Americans died, out of 1,198 total deaths. That number is why the event mattered so much in the U.S. even though the ship was British. ## Related Study Guides - [7.5 World War I: Military and Diplomacy](/apush/unit-7/world-war-i-military-diplomacy/study-guide/4wZDa2Pak8FfrKeucUqt) ## Structured Data ```json {"@context":"https://schema.org","@graph":[{"@type":"LearningResource","@id":"https://fiveable.me/apush/key-terms/sinking-of-the-lusitania#resource","name":"Sinking of the Lusitania — APUSH Definition & Exam Guide","url":"https://fiveable.me/apush/key-terms/sinking-of-the-lusitania","learningResourceType":"Concept explainer","educationalLevel":"AP / High School","about":{"@id":"https://fiveable.me/apush/key-terms/sinking-of-the-lusitania#term"},"audience":{"@type":"EducationalAudience","educationalRole":"student"},"dateModified":"2026-06-11T00:48:04.108Z","isPartOf":{"@type":"Collection","name":"AP US History Key Terms","url":"https://fiveable.me/apush/key-terms"},"publisher":{"@type":"Organization","name":"Fiveable","url":"https://fiveable.me"}},{"@type":"DefinedTerm","@id":"https://fiveable.me/apush/key-terms/sinking-of-the-lusitania#term","name":"Sinking of the Lusitania","description":"The Sinking of the Lusitania (May 7, 1915) was a German U-boat attack on a British passenger liner that killed 1,198 people, including 128 Americans, turning U.S. public opinion against Germany and starting the chain of events that ended American neutrality in World War I.","url":"https://fiveable.me/apush/key-terms/sinking-of-the-lusitania","inDefinedTermSet":{"@type":"DefinedTermSet","name":"AP US History Key Terms","url":"https://fiveable.me/apush/key-terms"},"educationalAlignment":[{"@type":"AlignmentObject","alignmentType":"educationalSubject","educationalFramework":"AP Course and Exam Description","targetName":"APUSH Unit 7, Topic 7.5, LO 7.5.A"}]},{"@type":"FAQPage","mainEntity":[{"@type":"Question","name":"What was the Sinking of the Lusitania in APUSH?","acceptedAnswer":{"@type":"Answer","text":"It was the May 7, 1915 torpedoing of a British passenger liner by a German U-boat off Ireland, killing 1,198 people including 128 Americans. 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