Tonight at 10 pm, almost seven years after it ceased production as a series on the Fox network, Simpsons creator Matt Groening and David X. Cohen’s science-fiction animated series Futurama will follow the example of Family Guy and premiere a season of 26 new episodes on Comedy Central. (Two batches of four new episodes each ran on this network in recent years.)
As before, the head of Richard Nixon in a plexiglass container (or whatever it’s made of) will play a recurring part on the show, set in 3010 or thereabouts. Not long after the series started in 1999, RN ran for the presidency of Earth and won under somewhat disputed circumstances. But as Futurama went on, and various bizarre and dangerous aliens threatened the planet, it became obvious that RN – and Dr. Henry Kissinger’s head – were the only two Earthlings who could successfully negotiate with such invaders. Therefore, the characters in the series have generally been willing to overlook both his irritation at hippies, and his habit of cutting Commander (or whatever his rank is; it always changes) Zapp Brannigan too much slack.

David X. Cohen, in this interview at Wired.com, explains why RN is so prominently featured in the series:

Dying in Futurama is a minor impediment. Richard Nixon is there more per hour than any other politician, because Matt Groening takes glee in the idea of resuscitating him. It used to be a one-time joke, but then we decided to have him re-elected early on.