I spent part of this summer in New York, and the city that once called itself the capital of the world is visibly fraying. Cracked roads, broken sidewalks, neglected buildings, and a subway so hot and filthy that it is hard to breathe in. This is the city where the new radical Left has become a governing force. And during Pride Month, I saw where that force comes from.I saw the Soviet flag. Not as irony, not as a museum piece — as a demand. Young Americans carrying the hammer and sickle, in shirts calling for socialism to be built here and capitalism to be torn down. I grew up under the real thing. I reviewed the KGB archives in Tbilisi, Georgia, in 1996 with my own hands. I know what that flag cost the people who lived beneath it. To see it waved as a fashion statement in the richest city on earth is not nostalgia. It is amnesia, organized and on the march.For years, the comfortable story in Washington was that the Democratic Party remained, at heart, the party of President John F. Kennedy, or at least of former President Bill Clinton. That story is no longer true. The party’s institutional machinery is being captured, methodically and structurally, by a faction that calls itself the Democratic Socialists of America. This is not a label I am pinning on them: Many members openly identify as socialists and Marxists, and the group’s revolutionary caucuses describe themselves as communists outright.