First, Bob Shieffer did an incredible job moderating the debate. He set out clear expectations and showed confidence in enforcing them without getting in the way.
Second, the format was great. Maybe it was just that the other two formats were so bad, but tonight's set up allowed the candidates to engage and show a real contrast. Now for the candidates...
John McCain has already been called angry and erratic. He couldn't have disproved that label tonight. Instead he used emotion to some advantage. He went on the attack and made points that will keep his base excited. For me, the attacks on ACORN and William Ayers fell flat, but I'll bet conservatives were cheering. Where his attack was effective with me and maybe some in the middle was his distancing from President Bush. Not only did he say he isn't George W. Bush, he added that maybe Barack Obama should have run against him four years ago. I remember the 2000 campaign, and John McCain with all his flaws is no George Bush. McCain was on the offensive and he had to be. I think some of the attacks got to Obama a bit.
But the attacks didn't land a devasting blow against Obama. Obama was strong in the details of his plans, convincing in his rationale for choosing Joe Biden as his running mate, and he was courageous in defending Roe v. Wade. When he said the right to privacy shouldn't be subject to a state referendum, I found myself nodding. It's not so much that he defended that issue, but it's the fact that he defended a hard issue with clarity that Democrats have been cautious about for the last few years.