Rick Santorum is his own worst enemy. That’s become a truism with regard to his penchant for hot-button rhetoric and his inability to resist the urge to go wildly off-topic and off-message. But it is also true in a more important and fundamental way: He is entirely lacking in executive skills. And that’s a problem when you are presenting yourself as a potential chief executive and commander in chief.

Santorum has relied on the same nucleus of aides, less than a handful of them. Former chief of staff Mark Rodgers and political consultant John Brabender have been with him for years. That’s about it when it comes to top-level advisers. Unfortunately, neither one is a policy guru, neither has been in charge of a presidential campaign and neither has much ability to correct or restrain Santorum when he goes astray.

As Politico reports, no other candidate has a “team of top strategists as insular as Santorum.” And this has left him without top-flight advice. “The touch-and-go quality to the campaign, which many find endearing, also leaves the candidate exceptionally vulnerable to his own shortcomings. Around Santorum, there’s no protective layer that can stop him from spouting off on, say, John F. Kennedy’s view of church and state. There are few aides who can nudge him toward a more disciplined, sustained set of talking points. With few surrogates and senior aides at his disposal to hold press calls and hit the cable circuit, Santorum has found himself consistently outgunned by Romney in the messaging department.”

His unwillingness to build a more competent and experienced staff even now that he has the financial resources to do so suggests either a excessive need for control or a mistrust of outsiders, neither quality suggestive of presidential-caliber talents.

Again and again Santorum has tried to present his fly-by-night organization as somehow morally superior to the well-oiled and -run Romney operation. He brags about his lack of staff and his funding deficit, as if one gets points for fewest dollars spent or fewest staffers hired. But is there no virtue in incompetence and disorganization.

Take his refusal, even in critical settings, to work from a prepared text. He insists that he not use a teleprompter (or apparently any prepared text): “See, I always believed that when you run for president of the United States, it should be illegal to read off a teleprompter. Because all you’re doing is reading someone else’s words to people.” What about reading his own words that have been carefully considered and organized in advance? (Again, notice the unwillingness to delegate or accept input from others.)

There are also the missed ballot filings. And let’s not forget failure to do oppo on the candidate himself and prepare for entirely foreseeable attacks from the media and his rivals.

It is not surprising Brabender would defend the current setup: “Is it Mitt Romney’s sort of bloated, establishment, federal government-style campaign? No. But part of that is by design. I think probably if you compared us to Gingrich’s campaign, I think we’re probably much more sophisticated.” But Newt Gingrich, of course, is losing badly, trailing even Santorum, who is now far behind Romney’s delegate total.

This is the difference between winning the Iowa caucuses — where you can drive a truck around the state for months talking about anything and everything — and running a winning presidential campaign. It’s the difference between running a Little League team and a major league ball club.

Whatever the reason for the failure to create an appropriately sized and sophisticated operation, it is revealing of Santorum’s flaws. He’s a legislator, not an executive. He seems to have a rather large chip on his shoulder (remember the whining in the debates that he didn’t get enough questions and that his Senate experience wasn’t properly appreciated?). Like Sarah Palin and Gingrich, he too often casts himself as the victim (of the press, mostly). None of these is a fatal defect, but when coupled with his inability or unwillingness to build and manage a team that compensates for his shortcomings, his campaign begins to sputter and he becomes less credible as a presidential candidate. If he seems less “presidential” than his chief rival, it is because he is.