The Republican presidential race is about to slow down.

Super Tuesday's frenzy of voting across 10 states could lead the race in several different directions. But virtually all of those paths will lead to Mitt Romney winning the nomination.

While no one is mathematically close to clinching the nomination, Romney is already far and away the delegate leader. He's padded his lead with four straight victories in primaries and caucuses, capped by a win Saturday in Washington State that leaves him with an estimated 184 delegates, to Rick Santorum's 91, according to ABC News calculations.

Critical Ohio is among the states up for grabs Tuesday, with Santorum slightly ahead in the most recent polls. A loss by Romney will raise new questions about his struggles to unite the Republican Party behind his candidacy, and would embolden Santorum to soldier on and continue to weaken the frontrunner.

But even a staggering Romney loss in Ohio won't keep him from winning more delegates than his opponents on the biggest day of voting yet.

Romney is continuing a march to the nomination that increasingly looks like it can't be stopped. The party establishment is starting to rally behind the man they know will almost certainly be their standard-bearer; this weekend brought an automated pro-Romney phone call in Ohio recorded by former first lady Barbara Bush, plus the endorsement of conservative leaders Sen. Tom Coburn and House Majority Leader Eric Cantor.

This is a week when organization matters - and when Romney's campaign juggernaut starts to flex its considerable muscle.

Santorum and Newt Gingrich failed to even gather the necessary signatures to appear on the ballot in Virginia. Romney is therefore virtually assured of securing all 59 of the state's delegates in a state where the only other candidate on the ballot will be Ron Paul.

In Ohio, Romney is favored to win the lion's share of delegates even if he loses the state. More Santorum organizational failures could make it impossible to win as many as 18 of the state's 66 delegates, though issues surrounding those delegates could take weeks or months to hash out.

(Image Credit: Justin Sullivan/Getty Images)

With Romney-favored states including Massachusetts, Vermont, and Idaho also voting Super Tuesday, the chances of a Romney wipeout are remote. Complicating the anti-Romney forces' day is the fact that Gingrich is running strong in his native Georgia, the day's biggest prize, with 76 total delegates.

The net result is that even Romney's nightmare scenario - a loss in Ohio to Santorum and getting swept by Gingrich and Santorum in the Southern Super Tuesday states of Georgia, Tennessee, and Oklahoma - would likely still see him walk away with the most delegates.

Layer on that the proportional delegate allocation system in most states and it becomes clear that Santorum and Gingrich simply can't catch up fast enough to erase Romney's lead. The non-Romney candidates may have persuasive arguments, but they can't win by losing.

Romney may not surpass the magic number of 1,144 delegates until May or June. But the point is no other candidate is positioned to even come close to that threshold before Romney does.

Romney has had his flaws and foibles exposed by this extended primary fight. The commitment by Santorum and Gingrich to continue on could further undermine Romney's attempt to excite and unite Republicans behind his candidacy.

But Romney is in position to turn his claim on the GOP nomination from a question of if into one of when. A win in Ohio, while not critical, would put more pressure on Romney's rivals to exit gracefully, as the trend lines become clear.

After Tuesday, 22 states will have held contests to award convention delegates. Romney will be the sole frontrunner, and is positioned to pull away further from his rivals.