David Brock, the conservative journalistic assassin turned progressive empire-builder, is sitting in a conference room in the Park Avenue South offices of the MWW Group, a public-relations firm owned by Democratic mega-donor Michael Kempner. Fifty-two years old with a silver pompadour, and wearing round glasses with wire frames, he’s barely recognizable as the skinny, dark-haired operative who, during the Clinton administration, had an answering-machine message that said, “I’m out trying to bring down the president.”
