How Santorum knows he’s doing well

Over the weekend, it became clear that Rick Santorum, after months of having been largely ignored, is on track for a top-three finish in the Iowa caucuses. By some measures, the former Pennsylvania senator is coming on so strong in the 11th hour, he has a credible shot at actually winning in Iowa tomorrow.

And how does Santorum know for sure that he’s doing well? Because his Republican rivals who pretended he didn’t exist have started taking shots at him.

Late last week, Texas Gov. Rick Perry went after Santorum over earmarks, and former Massachusetts Gov. Mitt Romney took on Santorum yesterday over the length of his congressional career.

Though he began his answer by saying that he had not “spent a lot of time trying to describe differences on policy and detail among myself and the other candidates,” [Romney] went on to contrast his background with that of Mr. Santorum and former House Speaker Newt Gingrich.

“Like Speaker Gingrich, Senator Santorum has spent his career in government, in Washington — nothing wrong with that,” Mr. Romney said. “But it’s a very different background than I have….”

It’s probably safe to assume Romney’s internal polling is similar to what all the other polls are saying: Santorum can’t be ignored anymore.

It’s also hard not to notice that Romney has one stand-by attack for just about all of his rivals. As Nate Silver mentioned last night, “Romney campaign seems to default to the ‘career politician’ line whenever it gets nervous.”

That’s true. When Perry looked like a leading challenger, Romney launched an aggressive “career politician” line of attack. When Gingrich was on top, Romney took the same tack. Now Santorum is closing strong, so he gets the same label. (Two weeks ago, Romney even used this against President Obama.) I have no idea why voters would find this persuasive, but the fact that Romney keeps using the line like a crutch suggests the focus groups must like it.

Regardless, when it comes to the substance, it’s worth noting a pesky detail: Romney and Santorum both first sought statewide office in 1994, when they both ran for the Senate. One was successful; one failed. Indeed, the most notable difference between them is the detail the former governor prefers to overlook: Santorum repeatedly earned voters’ support and has won most of his races for public office, while Romney has struggled with voters and lost most of his campaigns.

Romney, in other words, would be a career politician if only the public liked him more.