Ten states will vote on Super Tuesday — aka next Tuesday — but Ohio stands head and shoulders above the other nine in terms of importance.

Republican presidential candidate, former Massachusetts Gov. Mitt Romney speaks during a campaign rally at Capital University on February 29, 2012 in Bexley, Ohio. (Photo by Justin Sullivan/Getty Images)

A win in Ohio matters — a lot. And, for Romney, it’s uniquely possible that winning the Buckeye State on Tuesday would effectively clinch the presidential nomination for him.

“If he does, it’s over,” said Republican strategist Ed Rollins about the prospect of a Romney Ohio win. “All that’s left is convention speeches and the balloon drop.”

At the moment, former Pennsylvania senator Rick Santorum is still a slight — but slipping — favorite in Ohio. A Quinnipiac University poll released Friday morning showed Santorum at 35 percent to 31 percent for Romney. But (and it’s a big old but) that’s down from the seven-point edge Santorum held in a Q poll at the start of the week.

One pro-Romney operative familiar with the state of play in Ohio said that the “numbers are moving and anecdotal evidence shows a significant improvement since Michigan, but there was a lot of ground to make up.”

If Romney comes from behind to win Ohio as he did in Michigan, you can expect a major push from the party establishment, who has so far stayed out of the contest, to end the race.

A senior party strategist, granted anonymity to speak candidly, said that a Romney win in Ohio but would be a “tipping point”.

“It’s hard to see how Santorum credibly presses on if he loses Ohio,” added the source. “Republicans are getting weary with the primary and even those who don’t really like Romney will begin to coalesce behind him in order to move on to Obama, which everyone is increasingly anxious to do.”

That sort of establishment push could make it difficult for Santorum to raise money. And without money, it would be tough for him to remain a viable candidate.

Of course, if Santorum can pull out an Ohio win it’s a virtual certainty that the race will continue for several more months and could even go all the way to the Republican national convention in Tampa, Florida.

Below is our ranking of the 10 states set to vote on Super Tuesday. The number one ranked state is considered the most important for the four candidates. Agree or disagree with our picks? The comments section awaits.

To the Line!

10. Massachusetts: If Romney loses his home state — or comes anywhere close to losing it — it would be an upset of epic proportions. That said, there’s zero evidence Romney faces any sort of challenge in the Bay State.

9. Vermont: The Green Mountain State went heavily for Romney in 2008, and we would expect the same this time around. Say what you want about his vulnerabilities elsewhere, Romney owns the Northeast. The competition isn’t even trying here.

8. Alaska: This sparsely populated, distant caucus state is a genuine toss-up. There are no polls and little historic data, because Alaska traditionally votes too late to matter. Paul is the only candidate taking the trek north but Romney sent one of his sons, Gingrich held a tele-townhall and Santorum is on the radio. Romney’s frequent attacks on Santorum’s support for the “Bridge to Nowhere”could hurt him here.

7. Virginia: The Commonwealth would rank far higher up on the Line if all four of the remaining candidates were on the ballot here. But, due to a very high bar to qualify, the only two choices for Virginia Republicans on Tuesday will be Romney and Paul. Romney should win easily but that doesn’t tell us as much at it might have about his appeal in a state that could be the swingiest of all in the general election.

6. North Dakota: Romney’s visit to Fargo on Thursday solidified this as the second most important caucus state. Romney, Santorum and Paul have all been to the state in recent days. It’s a great opportunity for Santorum as a Midwestern/Plains state and for Paul as a caucus state. And it might actually be more competitive than Idaho because Romney doesn’t have a built-in Mormon advantage here.

5. Idaho: The most competitive of the three caucus states voting Tuesday, Idaho is friendly territory for Romney — a quarter of the state’s residents are Mormon. He’s been drawing crowds there like he does nowhere else. But Paul has targeted the state and is popular there too; it’s where he performed best in 2008, taking 24 percent of the vote.

4. Oklahoma: The Sooner State should be a win for Santorum — if you believe polling. If he can win Oklahoma, Ohio and Tennessee — well within the realm of possibility — he would, without question, be declared the winner of Super Tuesday and come out of March 6 with considerable momentum.

3. Tennessee: If you want a sleeper pick for Super Tuesday’s most interesting race, it’s the Volunteer State primary. Santorum is up big here early, but Gingrich could give him a run for his money. And if they split the conservative vote up, maybe Romney shoots the gap. A moderate businessman winning in Tennessee? It’s actually happened before -- plenty of times.

2. Georgia: “I have to win Georgia, I think, to be credible in the race,” Gingrich said Thursday. He’s right.Georgia is the state where Gingrich first rose to power, in the part of the country where he’s most popular. If he can’t make it here, he can’t make it anywhere. He faces competition from Santorum, who is courting the state’s evangelical vote.

1. Ohio: Think Michigan was fun? Welcome to Ohio. Ohio gets top billing because the campaigns have been spending the most money on ads here, Ohio has the second-most delegates at stake, and it’s a Midwestern state where it’s anybody’s ball game. But mostly, it’s because this is the biggest test for Romney, with the other three big primary states all residing south of the Mason-Dixon line.

Aaron Blake and Rachel Weiner contributed to this report.