Living or dead? I've got lists for both:
Living
Nancy Pelosi, Harry Reid, Al Franken, Alan Grayson, Ted Cruz, Rahm Emanuel, Bill Clinton, Ray Nagin, Kathleen Blanco, David Duke, Chris McDaniel, William Jefferson, Terry McAuliffe, Howard Dean, Ron Paul, Justin Amash, Newt Gingrich, Rod Blagojevich, Jim Traficant, Jon Corzine, Sarah Palin, Sharron Angle, Rick Santorum, Rick Perry, Jennifer Granholm, Barbara Boxer, Al Gore, John Kerry, Christine O'Donnell, Debbie Wasserman Schulz, John Edwards
Dead
John Calhoun, John Breckenridge, Jefferson Davis, Alexander Stephens, Franklin Pierce, James Buchanan, Andrew Johnson, Preston Brooks, Sam Houston, Andrew Jackson, Mitchell Palmer, J. Edgar Hoover, Joe McCarthy, John Schmitz, Bull Connor, Robert Byrd, Orval Faubus, Lester Maddox, George Mahoney, Ross Barnett, William Fulbright, Al Gore Sr., Albert Watson, Ed Gurney, Eugene Talmadge, Herman Talmadge, Richard Russell, Jesse Helms, John Stennis, Robert Taft, Henry A. Wallace, George McGovern, Hugo Black
Eh? I'd also have a problem with your listiing of George McGovern, among a few others overall given that some are irrelevant and such, but when considering your biases and priorities, you still have a dislike for Robert Taft?
In any case, the worst human being (of importance) in American politics is probably the one occupying the Oval Office or otherwise overseeing things, regardless of party. Something something morality and all that.