George W. Bush, Clinton, and Gore were all in heaven, and the angel said, "You must cross this river and we will judge how much you have sinned based on how far you sink."
Dubya goes first and gets up to his neck, but makes it across. He looks back and sees Al Gore walking on the water. He appeals to the angel saying, "He's sinned as much as I have, what gives?"
The angel says, "He's standing on Clinton's shoulders!"