A Cambridge, Mass., resident casts her vote Tuesday at a polling station… (Emmanuel Dunand / AFP/Getty…)
Mitt Romney can't clinch the GOP nomination on this Super Tuesday. But the former Massachusetts governor, with momentum building after a narrow but much-needed win in Michigan last week, can effectively put the contest out of reach with a strong showing on what is the busiest day yet in the 2012 presidential race.
It's likely that nearly as many votes will be cast today as have been cast in the entire GOP nominating contest to date. There are certainly more delegates at stake today -- 437 -- than the 300-plus awarded in the earliest-voting states.
Of the 10 states holding primaries and caucuses today, the marquee contest is in Ohio. The final round of polling there shows the race is a statistical tie between Romney and his lead challenger, Rick Santorum.
As he made his closing argument Monday, Romney tried to return focus to the issues that have long dominated the GOP campaign: the economy and the size and scope of the federal government.
"During this campaign there has been discussion about all sorts of issues," he said in Canton. "I keep bringing it back to more jobs, less debt and smaller government. That's what my campaign is about."
Santorum did not shy from the high stakes in Ohio, where he had led Romney by double digits in some polls as recently as mid-February. At a stop in Westerville, he said it was not quite "make or break," but would "be a huge deal."
Sixty-six delegates are at stake in Ohio. If the result is as close as polls indicate, Santorum and Romney may end up with a close split -- though the former Pennsylvania senator is at a disadvantage because he failed to file full delegate slates in three of the state's 16 congressional districts.
But as was the case last week in Michigan, the statewide popular vote will be the headline of the night -- allowing either Romney to make the case he's the presumptive nominee, or giving Santorum more time to make his case.
Looking elsewhere, Romney is well positioned to rack up a major delegate advantage in states such as Virginia, Massachusetts and Vermont. Tennessee is another state where Santorum had the advantage, but which is now trending toward Romney.
Newt Gingrich seems on a path to easily carry his home state of Georgia, setting up what his campaign sees as a "Southern strategy" he will continue next week when Republicans vote in Alabama and Mississippi.
Ron Paul, still the only candidate without a statewide victory, is hoping to pick up delegates in caucus states such as Idaho and North Dakota.
National polling indicates that Romney is beginning to consolidate his support, picking up segments of the Republican base that had long favored his rivals. It may be that after flirting with a long list of "anti-Romneys," the party's base is ready to "fall in line." But Romney has been on the verge of locking up the race before only to stumble.
One thing seems certain -- no matter what the outcome, the field of four will likely stay at four. But President Obama's campaign and national Democrats sense that Romney is now on an irreversible path to the GOP nomination, and have already come out swinging.
"In greater and greater numbers, voters are seeing that Mitt Romney will say anything to get elected," DNC executive director Patrick Gaspard said in a new memo out this morning. "He has tried to buy his way to victory and has taken extreme and out-of-touch positions that will alienate general election voters."
Here's an updated primer on the Super Tuesday states, ranked according to the number of delegates at stake:
Delegates at stake: 76
Polls Close: 7 p.m. EST
How it works: Thirty-four delegates will be awarded proportionally to any candidate receiving more than 20% of the statewide vote. The winner in each of the state's 14 congressional districts will earn another two delegates, and the second-place finisher will win one, unless one candidate wins more than 50% in a district.
2008 result: In a close three-way race, Mike Huckabee won 34% of the vote, followed by John McCain with 32% and Romney with 30%.
2012 advantage: Gingrich. A CNN poll released Monday had him easily ahead of his rivals. But Romney, who was in second place, should pick up some delegates in suburban Atlanta congressional districts where he also performed well four years ago.
Delegates at stake: 66
Polls Close: 7:30 p.m. EST
How it works: Fifteen delegates will be awarded on a proportional basis to any candidate receiving more than 20% of the statewide vote. If a candidate has more than 50%, though, he wins all 15. An additional three delegates will be awarded to the winner in each of the state's 16 congressional districts.
In both cases, voters are electing delegates who have pledged to vote for a particular presidential candidate. Santorum, as mentioned earlier, did not file delegate lists in all of the congressional districts.
The final three delegates are the elected state party leaders.
2008 result: McCain easily defeated Huckabee, 60% to 31%.