Texas Gov. Rick Perry travels with a phalanx of Texas state troopers, but has one policy aide. According to observers, he pumped his fists as he did his characteristic deep knee bend (like a preacher exhorting the congregation or a yell leader willing on the football team) before the debate at the Reagan Library, but seemed fatigued and groped for words as the debate wore on. He was chairman of the Republican Governors Association, but unlike George W. Bush, who quickly grabbed endorsements from 20 fellow governors, none of Perry’s peers has endorsed him. He wrote a controversial book but now won’t say if he really means everything in it. (Legalizing pot? Repealing the 16th and 17th amendments? Sending Social Security to the states?)

This is not so puzzling as it might first appear. An adviser for Mitt Romney tells me that during the 2008 campaign on an airport runway, Romney at one point turned to him and said, “I’ve started businesses. I ran the Olympics, but this is harder than anything I’ve done. I had no idea.” Romney now seems exceedingly relaxed and hyper-prepared. He has mastered areas of policy and collected sophisticated staff. He doesn’t need a script and doesn’t avoid substantive interviews. He knows how to do this.

But Perry and his staff, all longtime Texas confidantes, haven’t seen anything like this before. The command of information demanded of a presidential candidate, the pace of the campaign, the constant scrutiny, the expectation to learn and pronounce upon diverse policy issues, and the risk of a gaffe are without parallel. Perry has won the governorship of Texas four times, but incumbent governors virtually always do in that state. (The last incumbent Republican governor lost in 1982.) He nevertheless seemed not to realize in the last debate that more jobs were created under his predecessors. He struggled to explain why a quarter of Texans lack health insurance. (He said something about Medicaid waivers, but a rival campaign adviser says bluntly, “It was gibberish.”)

He’s aligned himself with the Tea Party but has lived opulently as governor and traveled extensively on the taxpayers’ dime. He first told campaign audiences that ordering mandatory HPV vaccinations was a mistake but seemed to forget that (or get his spine up) before defending his plan against repeated attacks in the debate. He’s not a man who likes to concede mistakes or let his competition score a point.

He also has the bad luck to be up against an opponent whose persona highlights Perry’s shortcomings. A Romney adviser tells me the campaign will continue to feature Romney in speeches, interviews and other settings that show off his smarts and convey his mastery of more than talking points. Will Perry be able to match that — or even get through a Sunday talk show or an editorial board meeting? That’s an open question now.

Romney’s staff perceives Perry’s Social Security gaffe as significant. Tim Kaine, a Democratic Senate candidate in Virginia, is already referring to it in fundraising appeals, tagging former Republican senator George Allen with the “out to destroy Social Security” label. If others follow, many Republicans will come to regard Perry as a drag on the party. Right now the Romney camp is focused on Social Security, but Perry’s book is chock full of disturbing and extreme positions, even for GOP primary voters.

In sum, Perry is a man of infinite confidence who has lived in a rather rarefied political atmosphere where Republicans dominate and no one presses him on policy matters, his favorable treatment of donors or his fiery rhetoric. He is used to adoring crowds, a compliant legislature and a local press corps that he likes to ignore or leave behind on state travels.

The impression is of a man who never planned a run and has not yet appreciated the extent of the undertaking. In some sense he’s much less prepared than Govs. Mitch Daniels or Chris Christie, both of whom comfortably delve into policy minutiae and have had to carry out major policy innovations in the face of substantial Democratic opposition. When he says “no one could have imagined” what a monstrosity HillaryCare would be, it suggests he was either out to lunch in the 1990s or thinks today’s voters have amnesia. Perry compensates with aggressive rhetoric, attacking in a single debate Dick Cheney, Karl Rove, Rep. Ron Paul (R-Tex.) and Romney. An aide for an opposing candidate says, “If you’re a Republican who wasn’t attacked, you should file a class-action lawsuit.”

Conservative donors, operatives and pundits who hadn’t spent much time combing through his record or imagined he’d be an empty vessel who could be mentored (by them, of course!) cheered his arrival. But as he progresses through the race, doubts persist. His choice of staff signaled that he’s not interested in dealing with Beltway policy gurus. The doubts will increase unless Perry demonstrates he can control his ego, refine his rhetoric, learn some policy particulars and solicit advice from experts who can compensate for the limitations of his Texas circle.

That’s a lot to expect of anyone. He can’t skate through. He’ll either have to stretch — emotionally, intellectually, physically — or he will fade. Bluster can take you only so far.