Republican presidential candidate Mitt Romney waves after voting in the Massachusetts primary in Belmont, Massachusetts, Tuesday, March 6, 2012. (AP Photo/Winslow Townson)

As of 11:40 pm Tuesday night, Ohio’s crucial Republican primary was too close to call, long after the polls had closed. With 91 percent of precincts reporting, Mitt Romney led Rick Santorum by just over 5,000 votes out of more than a million cast. Basically, Ohio is a tie.

Whomover ends up with the plurality in Ohio, the takeaway from Super Tuesday is the same: working class voters don’t like Romney, and it’s his greatest liability.

Romney avoided a decisive loss in Ohio by unleashing an advertising barrage in which he and his Super PAC outspent Santorum and Santorum’s Super PAC roughly four to one. It was a repeat of what happened in Michigan a week earlier. Santorum was ahead of Romney before the ad blitz and exit polls show that Romney has the same crucial demographic problem. Romney lost to Santorum in Ohio among voters making less than $100,000 per year and those without college degrees, just as he did in Michigan.

In November, the candidate who wins the Midwest will win the election. To carry the Midwest, the Republican nominee will need to dominate among white, working class voters. It’s possible that Romney’s weakness among those voters in the primaries doesn’t tell us much about how he would perform against Obama. “White, non-college educated voters are precisely the slice of the electorate where the President is weakest,” notes Leonardo Alcivar, a political consultant and veteran of Republican presidential campaigns. The ones choosing Santorum over Romney will probably choose Romney over Obama. But it’s also possible that Romney’s lack of personal appeal to white, working class voters holds true across partisan and ideological lines. In that case, while the current Santorum voters will back the eventual Republican nominee, Romney may turn off blue-collar swing voters. Maybe they will vote for Obama, or maybe they will just stay home.

Recent polls suggest Romney may not be strong enough among those voters to overcome Obama. As Ron Brownstein wrote in National Journal on Monday, polls show the primary has been taking a toll on Romney’s image among swing voters:

In the NBC/Wall Street Journal survey, Obama held a 50 percent to 43 percent advantage over Romney nationally, up from a 47 percent to 44 percent lead in the average of the news organizations’ polls during the second half of 2011, just before the voting began in the Republican race. What’s especially striking about the new survey is that it shows Obama has made his biggest gains among the group. that has consistently resisted him the most: white voters without a college education

In the NBC/WSJ surveys through the second half of 2011, Romney led Obama among those working-class white voters by a commanding 52 percent to 38 percent…. But in [the] latest survey, Romney’s advantage with those voters had shriveled to just five points—48 percent to 43 percent. By comparison, in 2008 non-college white voters backed John McCain over Obama by a resounding 58 percent to 40 percent; Republicans won even more of them (63 percent) in the 2010 Congressional election.

To win in November the Republican must perform even better among non-college white voters than McCain did. The Obama coalition consists of non-whites, educated whites and young people. As Jonathan Chait recently explained in New York magazine, that leaves Republicans with three paths to winning: making inroads among non-whites, driving up their margins among older white, working class voters or disenfranchising Democrats. They have pursued the latter two options. In so doing they have further alienated non-whites. A Fox News poll released Monday shows Obama beating Romney among Latinos 70 percent to 14 percent.

“[Romney’s] a fundamentally flawed candidate,” said Ohio Attorney General Mike DeWine, a Santorum supporter, on MSNBC. “He cannot really appeal to the average voters.”

It’s easy to see why. Romney is John Kerry, except that while Kerry served in Vietnam, Romney went to France as a Mormon missionary. He’s stiff and awkward, and he grew up privileged. In recent weeks, Romney has reinforced his patrician image almost every time he has spoken without a script. Romney went to the Daytona 500, and managed to make two gaffes: mocking fans for wearing cheap ponchos and saying that while he is “not the most ardent” NASCAR fan, he has several friends who own teams. The fact that Santorum has been inaccurately tagged as a biographically and substantively working class candidate is largely because anyone looks proletarian next to Romney.

This doesn’t mean Santorum would be the stronger Republican nominee. Santorum’s problem is the inverse of Romney’s: he consistently loses college educated voters and those making more than $100,000. He performs best among the very conservative and religious. His campaign is so disorganized that he did not get on the ballot in Virginia, and he failed to fill out delegate slates in congressional districts in Ohio. Exit polls show Santorum winning very conservative voters in Ohio, while Romney carries voters who are somewhat conservative, moderate or liberal.

Romney remains the favorite to be the Republican nominee. He entered Super Tuesday with the most delegates, and he will receive the most delegates from Tuesday’s primaries. (Romney won his home state of Massachusetts, the neighboring state of Vermont and Virginia.) He has out-raised his opponents and he continues to rake in the Establishment endorsements, most recently John Ashcroft, Eric Cantor and Tom Coburn. That’s partly because the corporate wing of the GOP thinks Romney is the most electable candidate. He probably is, but he may not be as electable as he needs to be.

According to the Huffington Post as of Monday, “In Oklahoma…Romney’s super PAC is outspending Santorum’s super PAC by nearly 50 to 1. In Tennessee that margin is 9 to 1.” Romney lost both states to Santorum on Tuesday. In Tennessee Romney carried only voters making more than $200,000. In Oklahoma he carried voters who make more than $100,000, but he lost voters making less than $50,000 by a wide margin.

If Romney is the nominee, his problem with less wealthy voters won’t stop him from winning the Southern states he lost on Tuesday. Those states are too Republican for it to matter. But his problem with the same demographic in the Midwest could be decisive.

“The question for working class white voters will be whether they vote,” says another Republican consultant. “When you look at recent polls, [Romney] is not beating Obama there. When a critical part of any close campaign is turning out your low propensity voters, how does Romney turn out unenthusiastic working-class white voters? I don’t think he can.”

Romney’s solution in Florida, Michigan and Ohio was to drown his less well funded opponent—first Newt Gingrich, then Santorum—in negative ads. It isn’t good for turnout, but if it depresses his opponent’s support more than his own, it works. That will presumably be his template for the general election. “I think that [Romney] will go incredibly negative on Obama,” says the GOP consultant. “I think that’s all he’s got.”

But does that work in the general election? “I don’t think the Mitt Romney strategy of outspending your opponent 4 or 5 to 1 will work against Barack Obama because you cannot outspend the incumbent president,” said Gingrich in his victory address from Georgia on Tuesday night.

Romney’s only appeal to downscale voters is his relentless focus on generating job growth. In his victory speech in Massachusetts Tuesday night, Romney used the word “jobs” nine times. If the economy keeps growing stronger, this may not be the trump card he believes it to be.

Of course, if Republicans took a different approach, they would not be so dependent on appealing to working-class white voters. “Beyond 2012, the primary process exposes a great challenge to the Republican Party,” says Alcivar. “In the years to come, [non-college white] voters will make up a smaller part of the electoral pie. The old adage that politics is about addition has never been more true. Republicans are fighting for a smaller and smaller piece of the electorate, while Democrats are fighting for growing numbers of newer voters—Hispanics, African-Americans and women. Long term, this won’t be a Mitt Romney’s problem, but the Republican Party’s problem.”