United States Enters the War
World War I in Europe and the Russian Revolution (6 April 1917)
Historical Map of Europe
With Russia crumbling, Germany moved to increase its pressure on the West. On February 1, it announced unrestricted submarine warfare in an attempt to starve Britain into surrender. This aggravated relations with the United States and, when German plans to incite a war between Mexico and the U.S. were uncovered, America declared war.