Senator Al Franken has been a little quicker with the humor in interviews this year, having established himself as a congressman who happens to be an ex-comedian. He gets in a few more zingers here in interviews with David Letterman in his new Funny or Die web-series Boiling the Frog, which looks at the politics of climate change. Here in episode 3, “Little Rhody," Rhode Island Senator Sheldon Whitehouse comes to explains the carbon tax to an uncertain Letterman, thinking he won’t get the complexities. Letterman starts by telling Franken, “OK, I’m not the dumbest man in America..."