"New Democratic Strategy Goes After Koch Brothers," announced a New York Times headline last week. Here's how the story began:

Charles G. and David H. Koch, the billionaire brothers who are perhaps the best-known patrons of conservative Republican politics, are bespectacled and in their 70s. They look genial enough. But Democrats are embarking on a broad effort that aims to unmask the press-shy siblings and portray them, instead, as a pair of villains bent on wrecking progressive politics. On Thursday, the Democratic Senatorial Campaign Committee is starting a digital campaign that will use Internet ads and...