Though Mitt Romney’s opponents continue to insist there is a road to the Republican presidential nomination for them after the Super Tuesday contests, the arithmetic suggests otherwise.

How long it will take for the other contenders and their supporters to figure that out — and to make peace with it — is another question.

There are several reasons that candidates this year may not have to reckon with the inevitable for weeks or even months.

The GOP nomination contest was designed to play out more slowly than in the past. Through the end of this month, states are required to allocate their delegates in proportion to the votes each candidate receives. That means just about everyone comes away from just about every contest with something to show for it — and a rationale for continuing to the next one.

And while the emptying of a campaign’s bank account used to spell the end for a candidate, Rick Santorum and Newt Gingrich have been kept on life support by billionaire supporters who have taken advantage of changes in campaign law to pour millions into independent super PACs that support the candidates.

At the same time, party leaders and rank-and-file Republicans are increasingly anxious to bring the process to a conclusion, to spare their eventual nominee further attacks from within the party fold. It is becoming more apparent that a lengthy primary battle could have a corrosive effect on the GOP’s prospects in the fall against a Democratic incumbent whom most Republicans are desperate to defeat.

“The next couple of weeks will be dominated by different groups of people accepting reality, which is that Mitt Romney will be the nominee,” predicted Steve Schmidt, a political strategist who ran day-to-day operations for GOP nominee John McCain in 2008. “There’s just not going to be much appetite in the Republican Party for a long, drawn-out primary when the outcome is clear.”

Going into Tuesday’s balloting, Romney had just over 200 delegates, according to Associated Press estimates — well short of what he needs to secure the nomination but more than twice as many as Santorum, who was running second at just over 90 delegates. Gingrich and Rep. Ron Paul (Tex.) were far behind.

Even if one of them were to begin performing far better than he has to date, it is difficult to see how he could make up the gap.

“Delegate-wise, it’s virtually impossible for Rick Santorum or Newt Gingrich to get to 1,144,” said Josh Putnam, a Davidson College professor who is an expert on the quirky rules by which Republicans in various states apportion their convention delegates.

Yet even Paul, who has conceded publicly that his “chances are slim,” plans to forge on.

In the coming weeks, despite a path to the nomination that looks surer, Romney may stumble a few times.

Santorum and Gingrich are both optimistic about their prospects in upcoming contests in the South, which is not hospitable territory for Romney. Mississippi and Alabama hold their primaries — which award a total of 90 delegates — next Tuesday.

Nor is Romney putting much effort into Kansas, which holds its caucuses on Saturday to determine who gets its 40 delegates.

“We have Mississippi and Alabama and Kansas, and I think I’ll win at least two out of three,” former House speaker Gingrich predicted Monday on CNN. His victory in his home state of Georgia, which offered the biggest single delegate prize Tuesday, is likely to bolster that confidence.

Santorum’s schedule on Wednesday and Thursday calls for the former senator from Pennsylvania to be in all three states as well. He was bolstered by victories in Tennessee and Oklahoma.

Meanwhile, early voting begins Saturday for Louisiana’s March 24 primary, in which 46 delegates will be at stake.

But in all of those states, convention delegates will be awarded under some proportional system, which means that no candidate is likely to get a significant burst of steam out of them — or to be entirely shut out.

The backing of rich patrons has kept gas in the tank for Gingrich and Santorum, but their operations lack the horsepower they need to run effective multi-state campaigns.

“We’ve always been a smaller, leaner staff,” said Santorum spokeswoman Alice Stewart. “It’s a logistical challenge when your campaign is based on a single candidate and a message.”

Of all of the challengers to Romney, Paul appears to be the most prepared for the long haul. His organization hopes to put in a better-than-expected showing in the remaining caucus states, which include Hawaii and Missouri in addition to Kansas, said spokesman Jesse Benton.

Paul is also focusing on rounding up stray unpledged delegates at upcoming district and state party conventions, Benton said.

Starting in late March and early April, however, the map begins to tilt in Romney’s favor. The former Massachusetts governor is looking to do well in Illinois’s March 20 primary, where 69 delegates are at stake.

Starting in April, party rules allow states to award their delegates on a winner-take-all basis — which throws some accelerant into the process.

Those will include the April 3 contests in Maryland (37 delegates), the District of Columbia (19) and Wisconsin (42).

Even bigger will be April 24, when Connecticut (28 delegates), Delaware (17), New York (95), Pennsylvania (72) and Rhode Island (19) vote.

At some point, the forces of momentum will overtake the forces of math and bring the race to a quick conclusion.