The DSA has had unprecedented success. It also has serious internal divisions.

Members of the Democratic Socialists of America gather outside of a Trump owned building on May Day on May 01, 2019 in New York City. | Spencer Platt/Getty Images It’s been quite a year for the Democratic Socialists of America. They got one of their own, Zohran Mamdani, elected mayor of New York City. They’ve taken down congressional incumbents in New York and Colorado. Their membership has soared to 120,000 dues-paying members, the group said. But with success has come more media interest —…