Some presidential candidates surge toward a nomination; some sneak up upon a nomination in the dead of night. Former Gov. Mitt Romney of Massachusetts, believing his hour has come round at last, at best seems to be slouching toward the 2012 Republican presidential nomination.

With a mixed result on Super Tuesday, Romney once again has missed an opportunity to put away the race, perhaps even to wrap up the nomination. And there are dangers ahead. Alabama, Mississippi and Missouri vote next week, and they are by no means natural Romney territory. But despite Tuesday night’s muddled finish, Romney remains in the best position eventually to capture the GOP prize.

“I’ve listened, and I’ve learned,” he said from his Boston headquarters Tuesday night.

And it is after mega-contests like the 10 conducted Tuesday that candidates girding for a long struggle often pause for introspection. If Romney does so, perhaps he might reflect on what he has learned thus far, not from the states he has won and lost, but from the rivals who have remained with him in the race:

l What Romney can learn from Rick Santorum

No major figure on the American political scene has been as far down as Santorum, who lost his own re-election battle by 18 points six years ago, used his wilderness years to make money and build connections, and finally began a presidential campaign that optimists called a long shot and realists called loony.

But with grit and creativity — and not inconsiderable study, especially in foreign affairs — the Pennsylvanian battled back, probing the established candidates for weaknesses, searching the political scene for openings. He visited all 99 counties of Iowa, a quixotic mission reminiscent of Richard Nixon’s doomed 1960 promise to visit all 50 states. But for Santorum that voyage underlined his resilience and established his reach.

Santorum, victor Tuesday night in North Dakota, Oklahoma and Tennessee, proved that a consistent message, repeated consistently, is a potent political weapon.

Unlike Romney, who is accused of changing his positions the way he changes campaign vestments, Santorum generally has avoided trimming his positions to the fashions of the seasons.

Even his greatest detractors, and Santorum’s detractors have deeper antipathy for him than critics do for any Republican in the field, would acknowledge that he is the Bartleby the Scrivener of the race, the figure from Herman Melville who would not go away and who would repeatedly offer the same riposte: “I would prefer not to.” If the GOP race were decided by pure determination, Santorum would be the nominee by acclimation.

l What Romney can learn from Ron Paul

If Santorum is Bartleby, then Paul, the Texas congressman, is Aram Khachaturian, whose “Sabre Dance” from the 1942 ballet “Gayane,” opens with 24 F-sharps in a row, a theme which is then repeated immediately, then transposed up a minor third for another iteration, which itself is also repeated.

For decades Paul, an obstetrician drawn into the political world, has expressed his impatience with the Federal Reserve, his skepticism of an interventionist foreign policy and his opposition to an intrusive government.

Romney’s position on abortion, by contrast, dates to 2006, the same year Massachusetts, under his leadership, passed a health care plan that Obama administration officials say was the model for the health care plan Romney so ardently opposes.

But Paul’s most compelling attribute is his frankness and his courage. He is willing to take the unpopular position and make the unpopular statement.

Republicans and Democrats alike were attracted to Sen. John McCain of Arizona in the best days of his Straight Talk Express campaign a dozen years ago, not because they necessarily agreed with his views, but because they admired his forthrightness and his readiness to break from orthodoxy. Romney has shown neither the instinct nor inclination to do so.

l What Romney can learn from Newt Gingrich

The former speaker has many flaws as a presidential candidate, but a lack of passion and a deficit of intelligence are not among them. In debates, in interviews and on the stump, Gingrich is passion personified, and his raw, sometimes unrefined intelligence was on display Tuesday night after winning Georgia.

That isn’t what won him the primary; his roots in the state did that. But it’s what kept him in the race, kept him going when all the smart people pronounced him a loser and a goner.

No one since John F. Kennedy has used presidential debates so artfully, and while Kennedy projected cool intelligence, Gingrich erupted with hot, intense acuity.

Moreover, Gingrich is the only candidate in the field who shows any joy in the process — not the politics of joy that Hubert H. Humphrey displayed in 1968, another fraught time, but a joy in exploring topics and themes that engaged his imagination, like space flight or zoos. Whether frightened by his zeal or fascinated by his effervescence, viewers and voters simply could not take their eyes off him.

l What Romney can learn from Mitt Romney

This is the hardest one.

The latest Wall Street Journal/NBC News poll showed that Romney holds a strong advantage over Santorum in being knowledgeable and experienced enough to handle the presidency.

The results Tuesday night showed that Romney has the capacity to project strength nationally, not just regionally — though the South remains a bafflingly elusive prize.

But what eludes Romney is a sense of ease and confidence. Instead, he seems tentative, awkward even, the prisoner of two terrifying truths — on the one hand that he is too scripted, and on the other that once he veers from the libretto he becomes a comic-opera figure spewing political malaprops, mostly about his wealth.

Romney can do almost nothing about Santorum’s advantage, according to the Journal/NBC poll, in being a reliable conservative, and he can perhaps do little about another Santorum advantage, caring about average people.

But if he shows he is comfortable with himself, he might go a long way toward making others feel comfortable with him. It’s the only attribute in politics that is contagious, and Romney still needs to catch it — and spread it.