At the end of the month, President Obama will deliver a string of punch lines at the White House Correspondents' Dinner. It's an annual tradition, a chance for the man at the top of the pyramid to poke fun at his political opponents and himself.
Humor is an essential tool in any politician's kit — all the more so in an age of instant, constant media. It can disarm an opponent, woo a skeptical voter or pierce an argument. This year, both Obama and presumptive GOP nominee Mitt Romney are using it to try to win the upper hand in the presidential race.