Campaign consultants are arguably now as famous in the United States as the politicians themselves. During the past decade, those who know the names Bill Clinton, George Bush, Newt Gingrich, and Christine Todd Whitman also recognize the names James Carville, Mary Matalin, Frank Luntz, and Ed Rollins. Professional consultants, once part of the privileged inner circle of presidential and gubernatorial candidates, are increasingly found at all levels...