Kentucky Senator Rand Paul was on the Late Show with David Letterman Thursday night.Paul was promoting his new book "The Tea Party Goes to Washington." Letterman asked the Senator about the Tea Party platform, and the conversation centered largely around tax cuts for wealthy Americans. It started with Letterman making a joke about Paul's decision to wear jeans with a tie and blazer and ended with a brief discussion of education funding and the protests in Wisconsin. You can watch the whole clip online.On a side note, while discussing the advantages of the private sector, Paul said Letterman can do better because he has to compete with other late night hosts. This set Letterman up for a joke about Jay Leno, but for astute public radio listeners, the conversation may be familiar. New York Times correspondent Bill Carter—who has written two books about late night television, one of which centers on the Letterman/Leno feud for the Tonight Show—recently discussed late night TV competition on The Sound of Young America. Carter says increased competition has made a few new stars (Letterman, Conan O'Brien, their writing staffs), it's also hurt late night in general by splintering the audience and ultimately weakening the power of the Tonight Show. Carter certainly wasn't arguing for state-run comedy shows or regulations on how many shows there can be, but his story connects to Paul's argument in an interesting way.