On Wednesday I wrote about Texas Gov. Rick Perry’s remarks at Liberty University, urging him to sound smart and shed the reflexive desire to pander to the strain of anti-intellectualism coursing through the GOP. My colleague Marc Thiessen points out that the remainder of his speech came across much better, with a loftier tone.

Marc’s column only underscores the puzzle: Why does Perry, who has things to say, not cut out the anti-smart routine altogether and lift his rhetoric and tone so that he makes a consistent, positive impression on voters? I think there are a few things at work here.

To begin with, Perry at this stage lacks specific policy positions on federal entitlement reform, national security, taxes and virtually everything else, with the exception of energy policy, which he understands quite well and can discuss at length. The “gosh I’m not too smart” routine is both a crutch and a time-filler.

Mitt Romney can talk without notes about 59 job proposals. Rick Santorum has a well-formulated approach to boosting manufacturing in the United States. But Perry can’t fill up the time at this stage with that sort of detail, so he resorts to Texas schtick and one-liners emphasizing his attachment to conservative populists. It suggests he hasn’t spent enough time on the substance of his campaign.

Moreover, Perry can’t resist tweaking the left even when it is not in his own best interest. That too is part of the Texas routine, with a smattering of Tea Party lingo. He doesn’t care for establishment Republicans either, as his snide remarks about “the cocktail circuit that would find some of my rhetoric to be inflammatory or what have you.”

The best GOP politicians — Rep. Paul Ryan (Wis.), New Jersey Gov. Chris Christie, former Florida Gov. Jeb Bush, Sen. Marco Rubio (Fla.) — have figured out that it’s important to deliver very conservative messages (on cutting spending, education reform, taxes, regulations and more) in a manner that appeals to the average voter without sounding unsophisticated. The best example I’ve seen of this was Christie’s speech earlier this year at the American Enterprise Institute where he blended no-nonsense talk, humor and smart policy. Ryan does the same in virtually every video or speech. Both politicians are wildly popular with Tea Partyers and still have the respect of policy gurus, business leaders and, yes, even the media.

It’s easy for governors to convince themselves they need no polishing. They travel like mini-emperors with a phalanx of security officers. They speak before raptured audiences. State officials butter them up on a daily basis. It’s misleading and ultimately debilitating. Perry can only get the votes of every Tea Partyer once — he needs to persuade others who are wary of his temperament or uncertain of his position on issues if he is to win the nomination and the general election. Perry shouldn’t change who he is, but he can mature, learn and grow during a campaign. For his own sake, for the GOP’s sake and for the country’s sake (he might become president, after all), I certainly hope he does. The next few weeks will be critical.