What is the legality of using a political figure's name, image, and reputation in parody?

Question

For example, if someone wanted to create a website that sold say, bumper sticker of the president's face with a quarky parody, would that be legal? I am pretty sure that it is, so long as it is in "parody", and that it is a political figure. If not, please explain where the line of legality lies.

Answer 1

If it is Republican, it is legal. If it is a Democrat, it is not.

Okay, seriously, politicians are public figures. Anything that can't be construed as a threat or as an incitement to violence is allowed.