Mitt Romney crushed President Obama in Wednesday's debate. The drubbing was so thorough that Obama's liberal allies in the media fancifully devised storylines about how Romney had somehow lost the debate by winning it.

Romney dominated on nearly every issue. On taxes, he refused to brook Obama's false claims about his own plan and attacked Obama's plans for tax hikes. He dominated on energy, pointing out Obama's wasteful subsidies for "green" sources of energy, along with a zinger about the subsidized firms that have failed: "You don't just pick the winners and losers -- you pick the losers." On entitlements, he put Obama on his heels by pointing out Obamacare's cuts to Medicare.

And on health care, Romney's weakest point, he held up without losing any ground. Whatever one thinks of Romneycare, Romney was quite convincing as he drew several distinctions between it and Obama's health care law -- that Romneycare was bipartisan, that it actually did allow workers to keep health insurance plans they liked, and that it came without any tax increases or looting of entitlements. This was more than enough to make an ill-prepared, low-energy Obama grimace.

But presidential debates are about more than just issues. They also offer voters a rare opportunity to see the candidates react in situations where there is little margin for error. As Herman Cain demonstrated in his own inimitable fashion, one need not necessarily know who is president of Uzbekistan, but it still matters how a candidate conducts himself in answering the question.

Romney's performance proved he is knowledgeable and confident. He had obviously prepared well, but he also came across as somebody for whom this level of focus and dedication is not unusual. He even seemed to be enjoying himself despite the pressure.

Obama, on the other hand, seemed uncertain, and at times clearly struggled for words. He lacked the presence of mind to bring up Romney's "47 percent" gaffe, Romney's career at Bain Capital, or Romney's tax returns -- the main themes of Obama's campaign so far. At one point, Obama even suggested that moderator Jim Lehrer please move along to the next topic. The dead-silent crowd and lack of TelePrompTer clearly put him outside his comfort zone.

Why did Romney succeed? Because he learned the hard way, suffering through the Republican Party's lengthy primary this year and losing the nomination to John McCain in 2008. Romney is also accustomed to facing tough audiences and hecklers (people don't faint at his speeches) and dealing with setbacks.

Obama, on the other hand, has lived a charmed political life. His only electoral loss came in a 2000 Democratic primary for U.S. House. He won his Illinois state Senate seat by throwing all of his opponents, including the incumbent, off the Democratic primary ballot. He won his U.S. Senate seat against Republican loose cannon Alan Keyes, who wasn't even from Illinois. After a tougher and longer bout with Hillary Clinton, with whom he had few ideological differences, Obama won the presidency against a hapless John McCain, under highly favorable circumstances. Until now, perhaps, Obama had never before faced a strong Republican opponent.

Obama is famous for his self-regard. He is Mr. Cool -- "eye candy" for female interviewers, he said last week -- and he thinks of himself as a writer and an intellectual. Perhaps as a consequence, he doesn't like to be challenged -- especially, as it turns out, by a determined, skilled and experienced Republican opponent.