British intelligence uncovered Germany's plans to form an alliance with Mexico against the U.S.
As a German submarine sank the U.S. liner Housatonic, all diplomatic relations with Germany
were severed. The first U.S. troops were sent to Europe in June.
Former U.S. Ambassador to Germany James Watson toured the country, explaining Germany's
threat to Europe and the U.S.
Puerto Rico became a U.S. territory.
Republican Jeanette Rankin of Montana became the first woman in the U.S. House.
Women's suffrage became law in New York state.
The Selective Service Act required all men aged 21 to 30 to register for the drafting into the U.S.