There is cool, and then there is cool to the point of ice cool. Barack Obama's coolness did not serve him very well tonight. He was fine, for the most part, on substance, but he did not parry effectively enough McCain's charges that he favored "defeat" in Iraq and that by potentially talking with Ahmadinejad he would be "legitimizing" the latter's views on Israel (and other matters). These McCain gambits should have been met with more force, passion, and heat than Obama displayed. I felt that Obama risked conveying that he did not care about these matters in a visceral way. There was no expression of, indeed no hint of, real outrage or even mild anger at the huge mess and disaster that the Bush administration has created in America's relations with the world. Obama said the right things but did not seem to feel them very deeply.
The upshot was, as Michael Beschloss remarked afterward, that Obama appeared to be on the defensive for a fair amount of the time. He was very good on certain topics like the U.S. and Pakistan, where he effectively criticized the U.S. record of largely uncritical support of (the now ousted) Musharraf. McCain came back with "I don't think Sen. Obama realizes that Pakistan was a failed state when Musharraf took over [by coup in '99] ." That's wrong: Pakistan was (and is) a very troubled state but not a failed state, and Obama should not have let that go by. He was also too willing to agree with McCain on the need for missile defense and on domestic nuclear power.
Obama had a strong moment at the end, when he talked about the decline in U.S. standing and reputation in the world, but here again he probably let McCain dissociate himself from the Bush administration without sufficient pushback. He even gave McCain credit on the torture issue -- gracious but probably unnecessary (and not wholly accurate). Judged from a transcript, this debate was probably a victory for Obama. Judged as television, however -- which means judged on the impressions conveyed and the tone, rather than as a purely substantive contest -- I would have to say McCain earned at least a draw, and perhaps should be given a slight edge for being on the offensive more of the time.
Bottom line: probably not many votes are going to be swayed by this debate one way or the other. But Obama better take a dose of de-icer before the next one.
P.s.: After reading D. Nexon's reaction (D. of Minerva), I am reminded that Obama also had a good moment on Iran and the impossibility of effective sanctions without the participation of China and Russia (in response to McCain's blathering about his League of Democracies).