"Politics makes for strange bedfellows," the old saying goes. Americans, however, often forget the obvious lesson underlying this adage: politics is about winning elections and governing once in office. Voters of all stripes seem put off by the rough-and-tumble horse-trading and deal-making of politics, viewing its practitioners as self-serving and without principle or conviction. Because of these perspectives, the scholarly and popular narrative of American politics has come to focus on...