On the verge of war, socialist movements started opposing the war because they believed that that war made workers killing each other in the interest of capitalist bosses. Not only socialist but anarchist, Christian pacifists and women opposed the war efforts. The Socialist Party of America continued its struggle against the war, which gained the support of labor unions and the government of the United States took strict measures like Espionage Act of 1917, to stop spreading anti-war feelings.
