Politico treated it the way we treat news stories nowadays, in our celebrity-driven culture in which a beloved actor’s suicide can drive front-page news for a whole week: “Media Matters’ David Brock expands empire,” it reported.David Brock may not be exactly an A-lister, but he is one of a contemporary cluster of insiders who have changed the way the “mainstream media” game is played. Bias, once the offshoot of genteel groupthink, has become progressively, aggressively organized. Advertisement Under the old model, Citizens for Responsibility and Ethics in Washington (CREW), which played a key role in bringing down Jack Abramoff and...