Socialist Trade and Labor Alliance

During its existence, the STLA essentially operated as the revolutionary, "dual union" wing of the SLP.

The STLA was formally founded at a meeting at Cooper Union Hall on Friday, December 13, 1895.

Speakers included William Brower, John F. Tobin, J. Mahlon Barnes, Lucien Sanial, and Daniel DeLeon.

It radically resented the established trade unions, like the American Federation of Labor; its Declaration of Principles asserted that "the methods and spirit of labor organization are absolutely impotent to resist the aggressions of organized capital".

Some in the IWW feared that DeLeon, who became an important leader in the organization, would attempt to make it a shadow of the SLP, as the STLA had been.