In this segment, Les Sinclair talks with historian Rick Britton about TODAY IN HISTORY. On the afternoon of May 7, 1915—106 years ago—the British ocean liner Lusitania, a 32,000-ton ship, was torpedoed by a German submarine off the south coast of Ireland. It sank in 20 minutes with the loss of 1198 passengers and crew, 128 of which were American. The attack provoked indignation in the United States, but Germany defended the action saying that the vessel had entered the war zone around Britain.

When World War I erupted in 1914, President Woodrow Wilson pledged neutrality for the United States, a position that most Americans favored. Britain, however, was one of America’s closest trading partners, and tension soon arose between the United States and Germany when in February 1915 Germany announced unrestricted submarine warfare in the waters around Britain. Soon, U.S. newspapers published a warning from the German embassy in Washington that Americans traveling on British or Allied ships in war zones did so at their own risk. The Lusitania had been warned, but the captain chose to ignore the warnings.

When it was revealed that Lusitania was carrying 173 tons of war munitions for Britain, Germany cited this as further justification for the attack. The U.S sent three messages protesting the action, and Germany apologized and pledged to end unrestricted submarine warfare. When 27 Americans were killed in another U-boat attack, however, public opinion in the U.S. began to turn against Germany.

January 31, 1917, Germany, in a bid to win its war of attrition against the Allies, announced that it would resume unrestricted U-boat warfare in war-zone waters. Three days later, the United States broke diplomatic relations with Germany, and just hours after that the American liner Housatonic was sunk by a German U-boat. On February 22, Congress passed a $250 million arms appropriations bill intended to make the United States ready for war. In late March, German subs sank four more U.S. merchant ships, and on April 2 President Wilson appeared before Congress and called for a declaration of war. On April 4, the Senate voted to declare war against Germany, and two days later the House of Representatives endorsed the declaration. With that, America entered World War I.