One year ago Rick Perry was not considered, by himself or by just about anyone else, a potential presidential candidate. His performance in last night's Fox News/Google debate in Orlando showed why.

Perry has been leading all the other Republican candidates in every national poll taken since he announced his candidacy on Aug. 13, upstaging the Iowa straw poll that Michele Bachmann won the same day. But in the debate, he showed himself still unprepared to answer some obvious questions and unsteady in his responses to attacks from others.

This was apparent in his response to the opening question on jobs. Perry once again cited Texas' genuinely superior record of job creation and, apparently in response to Mitt Romney's gibe in the previous debate that he benefited from past policies, noted that his 2003 measure limiting trial lawyers was partly responsible.

But his suggestion that he would sponsor national tort reform is in tension with his championing of state's rights. Romney responded by again citing his business record and segued into his claim that Barack Obama "has done everything wrong."

Perry and Romney were both prepared with attacks based on what the other had written in his books--and both disputed the others' readings. The resulting tussle left Perry looking defensive on Social Security and Romney on his Massachusetts health care plan, but Romney's defense later in the debate was smoother.

Similarly, Perry made a sharp point when he charged Romney with backing Education Secretary Arne Duncan's Race to the Top program, but Romney's response, including an attack on Obama for opposing the D.C. school choice program, was more detailed and assured.

"Americans don't know which Romney" they're dealing with, Perry said, in the sharpest interchange between the two during the debate. "We'll wait till tomorrow to see which Mitt Romney we're dealing with tonight."

But Perry stumbled while trying to nail Romney for changing his positions on gun control, abortion and health care. Romney was more self-assured when he responded by saying that he stood by every word in his book published two years ago while, he charged, Perry was not standing by what he wrote about Social Security in his book published six months ago.

Perry's best moments came when he was asked about immigration and gave answers that he knew the Orlando audience wouldn't like. The other candidates bragged about supporting a border fence, which Perry has opposed on Texas' 1,200-mile border along the Rio Grande.

"No one has spent more time on border security," he insisted, and attacked the Obama administration for lax border enforcement. And he vigorously defended Texas' law providing in-state tuition for children of illegal immigrants--brought in through no fault of their own, he said, and in need of education so they wouldn't become a public burden.

As Perry explained, these are consensus positions in Texas, though unpopular with Republican primary voters elsewhere.

Perry has spent 10 years as governor of Texas, and only a few weeks preparing to be president of the United States. He still has to think about his answers, and he has seemed fatigued in the second half of all three debates he has entered.

Romney, by contrast, has been campaigning for the presidency for more than four years, and is so trained up that he can seemingly go on autopilot when answering most questions. The results is a smooth, practiced delivery that makes him seem more presidential at this point in the campaign.

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