Why? It sounds like he was a number two term president.

It was somewhat of a joke;) He completed Kennedy's term and and was only only elected once. He refused to run for a 3rd. Given the immense ego's of these guys one might assume it was because he was unlikely to win. Peeing on people is unlikely to win you a lot of friends.

These days, stunts like that might get you a third term.

Well, one and a half.