Just as they sought to destroy John Kerry in 2004, the founders of the Swift Boat Veterans for Truth group are aiming their guns at this season's presumptive Democratic presidential candidate. But unlike four years ago, when the Swifties spent millions to discredit Kerry, their hit on Barack Obama so far hasn't cost them a dime. The opening assault came over the weekend in the form of a mass email to would-be sympathizers. "As liberal as Kerry was, America faces an even more liberal threat today: Barack Obama," wrote John O'Neill, a founder of the Swift Boat Veterans for Truth...