The Lusitania was sunk in 1915 and the US did not enter the war until almost two years after the sinking.
Answer:
On May 7, 1915, less than a year after World War I (1914-18) erupted across Europe, a German U-boat torpedoed and sank the RMS Lusitania, a British ocean liner en route from New York to Liverpool, England. Of the more than 1,900 passengers and crew members on board, more than 1,100 perished, including more than 120 Americans.
