McCain on Letterman

John McCain appeared on The Late Show with David Letterman tonight and took his sense of humor for a spin.

McCain looks like "the guy at the hardware store who makes the keys," "the guy who can't stop talking about how well his tomatoes are doing," "the guy who points out the spots they missed at the car wash," Letterman said.

McCain appeared and told Letterman, among other things, "You look like the manager of a creepy motel."

Letterman's jokes were better. But, hey -- he's the host. (And when we're talking about the writing on Letterman, remember that all things are relative.)

McCain took on several serious issues, including his rocky start as the presumptive nominee and the rejection of his candidacy by several prominent conservatives, the credit crisis and Guantanamo Bay. He showed off some wonkishness on the major issues -- McCain was perhaps at his best talking with passion about educational training programs at community colleges, one piece of the solution he envisions to the economic crunch facing the country -- but also showed a humorous, human side.

McCain's appearance was booked as part of his "biography tour," put together by his campaign as he slips his toe into the waters of a general election campaign and test-drives the message he'll need to win it.

If all I knew about McCain was what I saw tonight, I'd be impressed ... all in all, his strategists should be pretty happy -- and not just because of the latest RealClearPolitics polls.