On a sticky evening in July, leaders of the surging democratic socialist movement in New York City jumped onto Zoom to begin crafting the next phase of their campaign. Democratic socialist candidates had just toppled five incumbents, capturing two House primaries in the city and a handful more in state legislative races. But with an off-cycle election year ahead, leaders in the city’s chapter of the Democratic Socialists of America were shifting their focus from winning votes to changing policy. The group’s next order of business, its members agreed in the nearly hourlong Zoom, is to pressure Gov. Kathy Hochul,...