Mitt Romney finally shook off some big demons in Illinois on Tuesday night — ones that have haunted him this entire race. 

For the first time since Rick Santorum’s surge, Romney ate into large pieces of the former Pennsylvania senator’s base and, in some cases, swallowed them whole, expanding his support among younger voters, the middle class and Tea Party backers.

Younger voters:

One of the most consistently powerful and under-reported occurrences has been Mitt Romney’s reliance on seniors to inch him over the top in close states. For example, in Ohio, Santorum beat Romney in the four youngest age groups, stretching to age 50, but Romney pummeled him by 16 percent with seniors — enough to give him a narrow 1 percent win.


The story was the same in Michigan. Santorum won voters up to age 50, while Romney destroyed him by, once again, 16 percent among seniors.   

But according to CNN exit polls, in Illinois something new happened — Romney actually won younger age groups. To be sure, he still dominated with seniors, but he also won voters aged 30 to 44 and 45 to 64, speaking to the kind of broader demographic appeal that eluded him in previous Midwestern states. That more uniform distribution is a sign that he’s starting to expand his coalition. 

If a Republican is going to defeat President Obama, he’ll have to carry more than senior citizens, which is the only age group Sen. John McCainJohn Sidney McCainThe Memo: Powell ended up on losing side of GOP fight A pandemic of hyper-hypocrisy is infecting American politics Virginia race looms as dark cloud over Biden's agenda  MORE (R-Ariz.) won against Obama in 2008. Romney still has a long way to go with younger and middle-aged voters, but he finally subdued Santorum with that key demographic on Tuesday night.

The middle class:

If there’s one thing people know about this GOP race, and if there’s one convenient way of explaining it to your grandmother or grandfather, it’s that Rick Santorum is the blue-collar candidate and Mitt Romney is the white-collar candidate.

And, in fact, that’s what we’ve seen, so far, in Midwestern states — those legendary crucibles for class politics. 

In both Ohio and Michigan, Santorum beat Romney in households making less than $100,000 per year. In fact, even in Romney’s home state of Michigan, Santorum won every subgroup in the under-$100,000 crowd — including those making under $30,000 per year, $30,000 to $50,000 per year and $50,000 to $100,000 per year. 

But in Illinois, all but one of those categories flipped to Romney. In other words, both the middle class and working class finally shifted to support the former Massachusetts governor. The margins weren’t big, but the symbolism was — Romney carried income groups and classes he couldn’t even pull off in his home state.

Once again, Romney managed to put meat on the bones of his previous performances. In earlier states, he used huge margins with seniors and higher income groups to eke out small wins. On Tuesday night, he used broader margins with everyone to score a solid win.

Tea Party supporters:

Romney also made gains with one of the more historically hostile groups to him — Tea Party supporters. (It’s not easy to clearly define in a poll who, exactly, is a Tea Partier, but the best approximation is whether a voter says he or she supports the movement.)

In Michigan, Romney and Santorum tied with that group, and in Ohio, Santorum won. But Romney actually pulled out Tea Party supporters by 8 percent in Illinois, and nearly ran even with Santorum among those who strongly support the movement.

That’s a remarkable turn, considering a history colored by activists’ fierce resistance to Romney and his own lukewarm embrace of the movement. Of course, it’s doubtful he can replicate that in the South and Saturday’s Louisiana primary, where conservatives are more conservative and Tea Partiers more, well, Tea Party. But the Midwest means much more in the general election, and if Romney can win Tea Party sympathizers in a primary, that bodes well for him in November.

The holdouts:

There were a few groups that remained resistant to Romney in Illinois — even in the face of his strides with other important demographics. Evangelicals, rural voters and the “very conservative” continued to side with Santorum by double-digit margins that were only slightly less pronounced than in Ohio and Michigan.

Romney might never win these groups over, but Obama lost significant Democratic demographics in his 2008 primary battle, only to win them handily in the general, and there’s no reason to suggest Romney can’t do the same.

Conservative, religious and rural voters, though, would also be the biggest foes of President Obama, and in theory, that would make them Mitt Romney’s biggest allies in the general election.