The Nonpartisan League was an agrarian movement begun in 1915 in North Dakota that soon spread to Minnesota. League members protested the poor market conditions of farmers. The League advocated economic reforms to relieve the plight of farmers, who were exploited by middlemen in the grain elevator, packinghouse, stockyard, and cold storage industries. Decried as socialist from its inception, the League actually rejected the third party approach, choosing instead to endorse whichever candidates pledged to support their program. Once World War I began, Leaguers were ruthlessly attacked as disloyal pacifists, and the Minnesota state government, through the Commission of Public Safety, was instrumental in crushing the League in 1918. After the war, these events led the U.S. Supreme Court to rule that the guarantees of the Bill of Rights must be protected from state interference.