Sen. Rand Paul's filibuster last Wednesday placed the Kentucky Republican and Arizona Republican Sen. John McCain on opposite sides of a generational divide in their party that goes beyond ideology.

That flared into an open spat as McCain hissed: "The country needs more senators who care about liberty, but if Mr. Paul wants to be taken seriously, he needs to do more than pull political stunts that fire up impressionable libertarian kids in their college dorms. He needs to know what he's talking about."

That peevish retort may have reflected McCain's sense that he had been badly upstaged. Or maybe he hadn't followed the debate. With near-perfect timing, Paul got his response in a two-sentence letter from U.S. Attorney General Eric Holder. The first sentence was dishonest: "It has come to my attention you have now asked an additional question: 'Does the President have the authority to use a weaponized drone to kill an American not engaged in combat on American soil?' " In fact, that was Paul's question all along. But Holder then admitted, no, the U.S. government doesn't have the authority to target U.S. citizens at home who are not involved in hostilities.