To stop defeatism at home, Wilson pushed the Espionage Act of 1917 and the Sedition Act of 1918 through Congress to suppress anti-British, pro-German, or anti-war opinions. He welcomed Socialists who supported the war like Walter Lippmann, but would not tolerate those who tried to impede the war efforts, many of whom ended up in prison. His wartime policies were strongly pro-labor, and the American Federation of Labor and other unions saw enormous growth in membership and wages. There was no rationing, so consumer prices soared. As income taxes skyrocketed, white collar workers suffered. Appeals to buy war bonds were highly successful, however. Bonds had the result of shifting the cost of the war to the affluent 1920s. Wilson set up the United States Committee on Public Information, headed by George Creel (thus its popular name, Creel Commission), which filled the country with patriotic anti-German appeals and conducted various forms of censorship..

Between 1914 and 1918, the United States intervened in Latin America, particularly in Mexico, Haiti, Cuba, and Panama. The U.S. maintained troops in Nicaragua throughout his administration and used them to select the president of Nicaragua and then to force Nicaragua to pass the Bryan-Chamorro Treaty. American troops in Haiti forced the Haitian legislature to choose the candidate Wilson selected as Haitian president.

After Russia left the war and became a pawn of Germany, Wilson supported the "White" side of the Russian civil war, with a naval blockade and with ground forces in Murmansk, Arkhangelsk, and Vladivostok.