Scaremongering about democratic socialist Zohran Mamdani, who is now the mayor of New York City, closely resembles elite efforts over a century ago to stop socialists from winning another big-city mayoral race. On the eve of Milwaukee’s April 1910 election, one Democratic newspaper advertisement warned that under a socialist city hall “capital will be idle. The workingman out of employment. No man or party that advised the use of Guns and Bullets should be trusted with the government of our city. It will ruin the city’s credit.” Another campaign ad put things more succinctly: “PROMISES and DYNAMITE or EXPERIENCE and ACCOMPLISHMENT!”¹

Fortunately, most voters ignored these warnings. Socialist Emil Seidel won the mayor’s race, and Milwaukee’s socialists swept into office. Far from falling into ruin, Milwaukee and the state of Wisconsin at large prospered under socialist guidance over the next fifty years, pioneering many of the progressive, pro-worker policies that culminated in America’s New Deal. By 1936, even Time magazine felt obliged to run a cover story titled “Marxist Mayor” on this success, noting that under socialist rule “Milwaukee has become perhaps the best-governed city in the US.”

This history is rich in lessons for Mamdani and contemporary left activists looking to lean on city hall to build a working-class alternative to Democratic neoliberalism and Donald Trump’s authoritarianism. But the history of Milwaukee’s so-called sewer socialists — an initially derisive moniker referring to their zeal for improving public services — is much more than a story about successful left governance. The rise and effectiveness of the town’s socialist governments largely depended on the power and persuasion of a radical political organization rooted in Milwaukee’s trade unions.