At first, it seemed like just another example of Harry Reid being Harry Reid. The Senate majority leader, whose unscripted attacks can veer into bellicosity and take liberties with facts, spoke on the Senate floor last October and appeared to blame billionaire industrialists Charles and David Koch for the government shutdown. “By shutting down the government,” Reid said, “we’re satisfying the Koch brothers and Ed Meese, but millions of people in America are suffering.” In January, he went further, accusing the Kochs of “actually trying to buy the country.” His staff affectionately refers to such ad libs as Reid “getting...