In that regard, the wild Right of the 1950s, whether characterized by Joe McCarthy, the John Birch Society, or, worse, the Ku Klux Klan, has been entirely isolated from the mainstream conservative party. But is the same true of the Democrats, when Cindy Sheehan (Bush is the “world’s greatest terrorist”), Michael Moore (the terrorists in Iraq are “Minutemen), and Al Sharpton (still no apologies for his race-baiting violence of the 1990s) are welcomed into the fold,...