On Dec. 13, 1895 representatives of the Knights of Labor, the New York City Central Labor Federation, the Newark, N.J., Central Labor Federation, the
United Hebrew Trades, and the Socialist Labor Federation of Brooklyn organized the Socialist Trade and Labor Alliance. Led by
Daniel DeLeon, the STLA embodied the "new trade unionism" espoused by the Socialist Labor Party, a strategy to commit trade unions to support the party. In other words, members of STLA unions would
demonstrate solidarity at the workplace and in the voting booth.
The STLA expected its industrial unions to compete with, and ultimately replace, AFL craft unions. However that approach alienated many socialists and so did DeLeon's domineering personality. At its peak, the STLA never counted more than 30,000 members, mostly Jewish and German unionists in the New York City metropolitan area who generally worked in the clothing and shoe trades. In 1905, with about 1,450 members, the STLA joined the newly-organized
Industrial Workers of the World.