When war broke out in Europe in 1914, President Woodrow Wilson proclaimed U.S. neutrality and called on all Americans to remain “impartial in thought as well as action.” As the war in Europe escalated and Germany engaged in submarine warfare against passenger and merchant ships in the Atlantic Ocean, Congress feared that a loss of American lives at sea might elicit public demand for the United States to join the war. Concerned members of Congress pushed for legislation to reinforce American neutrality.