The Young People's Socialist League, founded in 1907, has operated as a semi-autonomous youth branch of the Socialist Party of America. In general its size has risen and fallen in consonance with that of the Socialist Party, and its activities have been geared to the needs of the parent body. But Y.P.S.L. members, or “Yipsels”, became differentiable from general party membership, particularly after the Russian Revolution, by their greater militancy and their eagerness to bring (in the League's slogan) “Socialism in Our Time”.
Often the Y.P.S.L. has exerted a Left pressure on the main body of Socialist Party members. In 1935 to 1936, the size and activism of New York Y.P.S.L. did much to swing the state organization in a radical direction. In the Social Democratic Federation, this brought about the exit of moderate adult socialists from the Socialist Party. In 1939 to 1940 the anti-war sentiment of Yipsels encouraged many socialists who favored aid to the Allies to drop their membership. At other times, the League has reflected its disaffection with the policies of Socialist Party leaders by cooperating with, allying with, or actually joining other adult radical organizations. In 1919 a majority of the League, then at its height with 10,000 members, broke with the Socialist Party to join the Workers Party (Communist). In 1937 to 1938 many Yipsels fused with the Trotskyists, expelled from the Socialist Party, to form the Socialist Workers Party. And again in 1953, a large percentage of Y.P.S.L. membership, then small in absolute terms, united with the Young Socialist League, youth affiliate of the Independent Socialist League.
In recent years the Y.P.S.L., in serious decline, has made itself felt primarily through larger, overtly liberal coalitions. In the 1930s and again in the 1950s many Yipsels exerted their efforts within the Student League for Industrial Democracy, later to become the Students for a Democratic Society. In the period immediately preceding World War II, many Y.P.S.L. members were active in the Youth Committee Against War. And in the early 1960s, Yipsels largely controlled the national policies of the Student Peace Union. More recently, Y.P.S.L., along with the Socialist Party, has lost almost entirely whatever influence it once exerted. Adopting the rigid anti-communism of the Socialist Party, the Young People's Socialist League has tended to dissolve into the liberal wing of the Democratic Party and the bureaucracy of industrial unions.
