Livonia, Michigan—Rick Santorum is running on fumes. His is the curse of insurgent presidential campaigns—too much passion and too little sleep.

You could hear it in his voice Monday morning talking to a Chamber of Commerce breakfast in Livonia as the decibel level grew higher, the diction grew muddier, and the logorrhea grew more obvious. An open-ended question on Social Security prompted a nine-minute Santorum monologue. Challenged from the audience about whether he was too conservative for the general election, Santorum out of nowhere unleashed a vicious non sequitur: “They mock conservatives, that’s what the media does. They mock the values that built this country.”

By any conventional measure, there is no Santorum campaign beyond his allied Super PAC and the bare infrastructure that makes his TV ads. Otherwise, it’s just the candidate winging it, as he did during the dark days in rural Iowa speaking to sparse crowds at the local Pizza Ranch.

This has not, for the most part, been an edifying spectacle. Impulsively deciding to counter Thursday’s Mitt Romney economic speech on the 30-yard-line of Ford Field, Santorum announced that he would be talking about his economic agenda late Friday night in a Knights of Columbus hall in Lincoln Park. The roughly 100 culture warriors (including fifteen nuns in full habit) waiting for Santorum expected a fiery attack on Obama and liberal permissiveness—not the 55-minute economic policy seminar on taxes, government regulation, and the plight of manufacturing that they received. 

The Michigan primary is the first high-stakes presidential contest in history that is a battle between two candidates each with MBAs and law degrees. But while Romney's campaign demonstrates the professionalism that you would expect with that pedigree, Santorum’s campaign is so amateurish that I feel almost tempted to pitch in with advance work just to uphold the traditional standards of presidential politics.

To weaken Santorum's insurgency, Romney hasn't even had to incite another round of Super PAC air wars, which were demonstrably more vicious in the skies over South Carolina and Florida. It was easy enough to simply goad Santorum into wasting endless time and energy trying to justify himself on ludicrous topics like supporting his home-state colleague, Arlen Specter, for chairman of the Senate Judiciary Committee in 2005. Listening to Santorum’s filibuster-length answers, I realized that you can take a man out of the Senate, but you can’t take the Senate out of the man.

Santorum's tragedy is that his campaign's lack of professionalism has undermined real advantages. Foremost among them are the manifest weaknesses of Mitt Romney himself. This is a candidate so uninspiring that he can’t even pull off a home-state Michigan pander. (At the Ford Field event in front of 65,000 empty seats, Romney burbled, “You know the trees are the right height, the streets are just right.” Ann Romney, in contrast, was dead-on by invoking a beloved local ginger ale: “If you cut us open and we bleed—we bleed Vernor’s.”)

Over the weekend, I spent two days interviewing Republicans at the Senate Coney Island in Livonia, which is a Greek diner (tip: great rice pudding) with its roots as a Depression-era hot-dog stand. Gary Cockfield, who runs an online business and lives in Redford Township, is my nominee for the emblematic Michigan Romney voter. When I interrupted him midway through a ham-and-cheese omelet Sunday to ask who he was voting for in the primary, Cockfield replied in the resigned tone of someone facing major dental surgery, “Probably Romney.” Even though Romney would probably carry the Senate Coney Island vote, the mention of his name prompted a bridge of sighs.

By contrast, Republican voters here have described Santorum to me again and again as “a genuine guy.” That's not to say that he's an exemplar of blue-collar America, a twenty-first century version of Archie Bunker. But because he did represent a dying-steel-mill congressional district and an industrial state, Santorum is able to exude man-of-the-people authenticity. Indeed, the threat from Santorum seems to have provoked Romney into a series of I’m-rich-and-you’re-not blunders. It’s not every week that a presidential candidate brags about his wife’s multiple Cadillacs and then after making a political pilgrimage to the Daytona 500 ruefully admits that he doesn’t follow racing closely, “but I have some great friends who are NASCAR team owners.” 

But though Santorum can speak movingly about the plight of displaced steelworkers in western Pennsylvania, he has never managed to coherently counter the GOP's reigning ideology, which rejects all attacks on the wealthy and their cushy tax rates as “class warfare.” The craving that many Michigan voters have for a Pat Buchanan-style right-wing populist has thus been left unsated.

In any case, Santorum has had too little money and too little sleep to plan a coherent Michigan campaign against Romney. That is the problem when the candidate is running a seat-of-the-pants campaign long on improvisation and short of strategic coherence. I am reminded of a fatigued John McCain who marred his 2000 New Hampshire primary upset of George W. Bush by picking a needless fight with Jerry Falwell going into the South Carolina primary. Howard Dean in 2004 also exemplifies this model. That is why, up until now, no under-funded and under-staffed insurgent has won a presidential nomination since Jimmy Carter.

What we do know on the eve of the Michigan primary is that Romney has been lucky in two spheres —in his business career and in the caliber of his 2012 primary opposition. Michigan may be Romney’s ancestral home, but this has turned into a primary made to order for a candidate like Santorum. If money and organizational muscle pull Romney into the winner’s circle Tuesday night, then it is Santorum—the tribune of Rust Belt Republican values—who should be haunted by might-have-beens.

Walter Shapiro is a special correspondent for The New Republic. He also writes the “Character Sketch” column for Yahoo News. Follow him on twitter @waltershapiroPD.