Why did John McCain choose to semi-officially announce his candidacy for the presidency Wednesday night on "The Late Show With David Letterman"? Maybe he needed to drum up some attention before his poll numbers slide any further. Maybe he wanted to stick it to Rudy Giuliani by making news in New York City. Or maybe, as Claremont McKenna professor Jack Pitney says, he just wanted to go somewhere he knew he'd be treated with kid gloves. "It gets him some attention without involving Iraq," Pitney tells the Arizona Republic. "If you're John McCain, you want attention that doesn't involve that albatross of an issue. He's not going to get aggressive follow-up from Letterman, and it's also a way to reinforce his image as a different kind of Republican."