The American Federation of Labor (AFL) was a national federation of labor unions in the United States that existed from 8 December 1886 to 4 December 1955. The AFL was founded by an alliance of craft unions disaffected from the Knights of Labor, and the Cigar Makers' International Union president Samuel Gompers served as its first president. After 1908, the AFL became closely linked with the Democratic Party, and its partnership with progressive employers disappointed socialists, who denounced labor's cooperation with capitalists. During World War I, the party allied with the government in crushing "radical labor groups" such as the Socialist Party of America and the Industrial Workers of the World, and the party opposed socialist political actions. In 1935, opposition to industrial unionism within the party led to the AFL expelling several unions, which coalesced into the Congress of Industrial Organizations (CIO). In 1955, the two unions merged to form the AFL-CIO labor federation.