In this threatening context, the United States has adopted an official policy of neutrality. In fact, between 1935 and 1939, Congress passed five different neutrality laws that prohibited U.S. participation in foreign conflicts. The impetus for these laws came from a resurrected American peace movement, revelations about the war profits made by American munitions companies during World War I, and a widespread belief among Americans that their intervention in the European war had been fruitless. Roosevelt tried to dilute these laws – which often made no difference between the aggressor and the victim – with mixed success.