Mitt Romney’s problems with conservatives and evangelical voters are well-established, but he’s also got a significant — if less readily apparent — issue with less-affluent voters.

And it’s a problem that could matter quite a bit in the next few weeks.

Rick Santorum is aiming for the upset of the 2012 presidential race in two weeks in Michigan, and if he can pull it off, everyone will be talking about how Romney can’t win over blue-collar voters.

A more precise statement may be that Romney has trouble with voters who are less well-off. But that’s really nothing new.

In every contest held so far in which exit polling is available, Romney has done progressively worse as a voter’s income has dropped.

Iowa, New Hampshire, South Carolina, Florida and Nevada all showed Romney performing between 8 and 20 percent worse among voters making less than $50,000, compared to those making more than $100,000.

And the two states with the highest percentages of voters making less than $100,000 — Iowa and South Carolina — happen to be the two states of those five that he has lost.

In Iowa, Santorum lost wealthy voters to Romney by double-digits but closed the gap thanks to his strength among the middle class. That’s a recipe he’s hoping to emulate not only in Michigan, but also looking forward to Super Tuesday’s biggest battleground — Ohio.

Michigan and Ohio both provide similar challenges when it comes to Romney’s under-performance with less affluent voters.

About one-third of voters in both states four years ago made less than $50,000, and nearly four in five voters made less than $100,000. If those numbers hold this year, these two states will present the least-affluent electorates we’ve seen so far in the 2012 presidential race.

What’s more, a Quinnipiac University poll released Tuesday showed the income gaps looming large again for Romney in Ohio.

While Romney led by 12 points among those making more than $100,000, Santorum led by 9 percent among those making between $50,000 and $100,000, and by even more than that among those making less than $50,000. Overall, that strength among poorer voters meant Santorum had a 7 percent lead.

In other words, the income disparity trend that has followed Romney through all of the early contests appears to be showing up in polls again heading into Michigan and Ohio.

It just happens that it will matter more in those two states.

Santorum says terrorists could strike North Dakota: Santorum said in an appearance in North Dakota on Wednesday that not even that state is immune from potential terrorist attacks.

“Folks, you’ve got energy here. They’re going to bother you. They’ll bother you, because you are a very key and strategic resource for this country,” Santorum said, according to CNN. “No one is safe. No one is safe from asymmetric threats of terrorism.”

North Dakota’s oil industry has thrived in recent years.

Emily’s List endorses in Walker recall: Emily’s List, the largest group dedicated to electing female candidates, is endorsing former Dane County executive Kathleen Falk (D) in the recall election of Gov. Scott Walker (R).

Falk recently got her first primary opponent: a female state senator who is not seen as a serious threat.

But by endorsing Falk now, Emily’s List may be trying to scare away anybody else from running — male or female. The group packs significant fundraising punch and even did independent expenditures in Wisconsin’s state Senate recall elections last year.

It is also backing Rep. Tammy Baldwin (D) in Wisconsin’s open Senate race this year.

Fixbits:

Romney was raising money Wednesday with Donald Trump at a law firm that specializes in bankruptcy.

Later, he promised a crowd in Michigan that he would take on union bosses.

Santorum releases four years of his tax returns., which show he made about $1 million in both 2009 and 2010.

More video has surfaced of Santorum speaking out against contraception. In a 2006 interview, he said it was “harmful to women.”

The New York Times reports that freshman Rep. Michael Grimm (R-N.Y.) went into business in recent years with a man who was indicted and later convicted of racketeering and fraud.

Rep. Jesse Jackson Jr. (D-Ill.) offers a very odd quote. Referring to his own personal problems — he faces a primary with former congresswoman Debbie Halvorson — Jackson said he takes inspiration from none other than Newt Gingrich : “To those who say the upside is gone, I look at Newt Gingrich and I am motivated and inspired what I could become. ... This too shall pass. This cloud shall pass.” Umm, OK.

Joseph Kennedy III officially begins his campaign to return a Kennedy to Congress on Thursday.

Must-reads:

Can Romney Rally His Suburban Base?” — Dante Chinni, PBS

Contraception battle looms in Mass. Senate race” — Steve LeBlanc, AP

Nevada, Massachusetts Key to Senate Control” — Stuart Rothenberg, Roll Call

Professor mounts campaign against inaccurate ‘super PAC’ ads” — Alana Semuels, Los Angeles Times

Will Mitt Romney have enough money for the primaries ahead?” — Dan Eggen, Washington Post

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