In a sign that he actually feels quite confident that he’ll finish well in Iowa (remember, he still intends to win the state), former Pennsylvania Sen. Rick Santorum said he’ll drop out of the GOP presidential race if he finishes “dead last” in the Hawkeye State.

“If I finish dead last in the mix I’ll go home but I don’t think that’s going to happen,” he said Tuesday on the Des Moines radio station WHO.

The former senator has been focusing his resources in Iowa and won endorsements from a number of the state’s top conservatives, including its Secretary of State Matt Schultz (R) and Bob Vander Plaats, the head of the social conservative group The Family Leader.

Unfortunately for Santorum, not even those endorsements have upped his standing significantly in the polls. According to RealClearPolitics, he has averaged just 7.7 percent support in the state, ahead only of former Utah Gov. Jon Huntsman, who has averaged about 4 percent but doesn’t plan to compete in the first-in-the-nation caucuses.

Perhaps even more significantly, he has tried but hasn’t been able to bag the endorsement of Iowa Rep. Steve King, who has said he wants a “full-spectrum conservative” as president. Santorum certainly fits that bill — but King has expressed doubt and reservation about whether Santorum (or Michele Bachmann, who King also considers adequately conservative) would be able to acquire enough support after Iowa to actually secure the nomination. Perhaps King’s endorsement is a tad overrated — this late in the game, it might not affect the race much — but his unwillingness to endorse even the candidates who most closely align with his views has nevertheless been a striking feature of the race in Iowa. Then again, King’s indecision might say less about Santorum’s ability to capture a larger share of support than he has in polls than it says about the indecision of Iowans, in general. Undecided voters could go to Santorum no less than to others.

For what it’s worth, The Washington Post’s lefty blogger Greg Sargent thinks Santorum has a slim chance not only to do well in Iowa — but to actually win the nomination:

[S]uppose that Santorum manages to rally to third place in Iowa, something that isn’t impossible to imagine. What then? It’s possible that conservatives who aren’t excited about Romney might look to him. And if he surged, then his main drawback – that there’s solid evidence that voters don’t like him very much – would suddenly look a lot less important.

Put it another way: We’ve seen what happens when the rest of the field surges (or, in some cases, simply shows up in the race). Large numbers of party actors have turned on Ron Paul and Newt Gingrich, and have opposed Michele Bachmann and Jon Huntsman. Their problems, whether policy (in the cases of Paul and Huntsman) or trust (Gingrich and Bachmann), cannot be resolved by popularity among the rank and file. But Santorum’s, to some extent, perhaps can.

So while I think the candidate most likely to benefit from an unexpected strong finish in Iowa remains Perry — the only candidate who actually showed some strength among party actors during his surge — I’m fairly convinced that Santorum is the next most likely to benefit if he should get the Iowa bump. Basically, if Romney has to match up against Paul, Gingrich, Bachmann or Huntsman one on one after the early states, I think Romney is as close to a lock as you can get in politics. Against Perry? I have no idea. I guess I’d say that Romney would be the favorite against Santorum, but I’m not at all sure that he’d be an overwhelming favorite. Or, to put it one more way: If there’s a 5 percent chance that someone other than Romney or Perry gets the nomination, I’m increasingly inclined to think that most of that 5 percent belongs to Santorum.

That doesn’t seem wholly implausible to me.