When Rashida Tlaib and Alexandria Ocasio-Cortez take office in January, they will become two of the first socialists to serve in Congress since 1950, the year that Vito Marcantonio finished his seventh and last term representing his New York City district. Although now largely forgotten, Marcantonio was a deeply popular politician whose feisty, theatrical campaign speeches regularly brought upwards of ten thousand supporters out into the streets of Manhattan.

A community organizer and labor lawyer, “Marc,” as his constituents affectionately called him, rode to office in 1934 on the strength of social movements demanding affordable housing and public jobs, and he stayed close to those and other struggles throughout his time in office. His efforts to legislate a radically redistributionist welfare state met with little success in Congress, but in other areas — above all civil rights — he advanced progressive policies farther than ever before.

Marcantonio, who was never a member of the Democratic Party, deftly exploited every ballot line while maintaining his independence with the backing of New York’s large and powerful left. While today’s socialists face a very different set of challenges and opportunities, they should take inspiration from his long (and long under-appreciated) career of pushing at the limits of the status quo.