Would he need to get permission to put the clip from Leave it to Beaver in the ad? I wouldn't think that they'd grant it.
I'm not a copyright lawyer, but I'd think it's in the public domain by now.
Nope.
For--profit corporations have commercials. Political campaigns have ads. A political campaign's use of copywrited music, images or footage is the quintessential example of the "Fair Use Doctrine" in play. No political campaign has ever been successfully sued for copywright infringement in federal court.
For example, a conservative 527 organization called "Club for Growth" used several seconds of the 50's classic "The Blob" in one of its ads. Although it was sued, after a year of litigation, the Club for Growth won. There is just significantly more latitude because it is not commercial use. The owner of the copywright would be hard pressed to show actual damages.
It is an interesting legal question, though. And we do get form letter nastygrams from time to time. But a political campaigns ads (it isn't commerce, so calling it a commercial is actually inaccurate...) enjoy core protected speech. There is no example of free speech that enjoys more protection than political speech. Whole statutes carve out political speech as an exception -- it even reaches parody material ( e.g. Saturday Night Live, Rush's parodies).
Here's another example -- Rush Limbaugh pays royalties for use of the "Pretenders" song for his show theme song -- but for his parodies, he isn't paying royalties for whatever material may use "copywrighted" material -- whole different world.
Glad you liked the ad. :)