The spotlight was hottest on Rick Perry, the frontrunner in national polls since he announced his candidacy in Charleston, S.C., on Aug. 13, the same day that Michele Bachmann won the straw poll in Ames, Iowa.
Perry's problem was not just that he punted on the tough question of how to respond to a terrorist takeover of nuclear-armed Pakistan. Even the smooth-talking Mitt Romney might have had trouble with that nightmare scenario. And Perry was right to cite our informal alliance with India as a source of leverage.
The problem was that Perry was couldn't respond cogently to utterly predictable questions and was unable to articulate his pre-scripted criticisms of Romney. A case can certainly be made that Romney has flip-flopped on issues. But Perry failed to make it.
Perry defended his order requiring HPV vaccinations by citing his talks with a woman with cervical cancer -- but they took place only after his order. He failed to fend off attacks on his criticisms of Social Security in his book "Fed Up!," saying he was only endorsing the longtime exemption from the program for state and local public employees.
He failed to explain why Texas, with its large legal and illegal immigrant and young populations, has a high percentage of people without health insurance.
He was eloquent in defending Texas's in-state college tuition for children of illegal aliens, but his stand is hugely unpopular with Republicans outside Texas. And he failed to point out that it helped him win a respectable 38 percent from Latino voters in the 2010 election.
Mitt Romney clearly benefited from his greater experience over the years and his superior preparation in recent weeks. But he also benefited from the fact that no one challenged him convincingly on claims that he is unlikely to be able to sustain.
He sloughed off Perry's accurate charge that he supported the Obama administration's Race to the Top education program -- a defensible position, but not a popular one for Republicans.
He repeated now what has been his standard defense of his Massachusetts health care program. But someday someone is going to nail him on his insistence that its individual mandate to buy insurance covers only 8 percent of the population. It actually applies to everyone.
He avoided Perry's claim that he deleted defenses of the program from the paperback edition of his book. He won't be able to deftly dodge that forever.
If he overtakes Perry in the polls -- a likely possibility after the Texan's stumbling performance -- he will likely become the pinata for the rest of the field, a role he figured to play before Perry entered the race.