This talk addresses a question that is often asked but seldom investigated in a systematic way. Why has radicalism found a home in certain locations in the United States but not others? It is a question made more complicated by the uneven history of the America left. Radical movements don’t last very long in the US and when new ones emerge, they are often very different than their predecessors. And the geography shifts. Some regions fostered left wing activism in one era but turned conservative in others. But the West Coast has a more consistent history. Why?