Milwaukee had Socialist mayors from the 1910s to 1960. They were “gas and water socialists” who were able to deliver services without the corruption and cronyism of the Democrats. The Republicans, then as now, weren’t that good at urban politics. People who voted for McCarthy and Eisenhower might well have voted for the last Socialist mayor. Of course, the DSA is more radical than the old Socialist Party, which largely closed up, thinking that FDR had given them what they wanted.
Milwaukee had Socialist mayors from the 1910s to 1960.
I learned that from Alice Cooper in “Wayne’s World”.