You can’t say Texas Gov. Rick Perry isn’t going all in to win Iowa. He’s spent far and away the most of any candidate. Mike Allen reports, “Rick Perry is the king of the airwaves, spending $2.86 million in December alone, according to ad tracking figures provided by the campaigns last week.” Another $1.33 million was spent by his super PAC.

However, it is far from clear it’s helping him. In the Public Policy polling survey released last night, he’s tied in Iowa for fifth place with Rick Santorum (who has an excellent ground game and can likely turn out his voters). Overall, in the RealClearPolitics average he is in fourth with 12 percent.

It’s safe to say that if he spends more than $4 million in ads alone in a rural state where Christian conservatives play a strong role, only to come in fourth or fifth, he’s pretty much done for. Unlike Rep. Ron Paul (R-Tex.), who has a rabid fan base to keep him going, or Santorum, who’s on the upswing and can run on a shoestring, it’s hard to see either the rationale or the means by which Perry could keep going after such a disappointing result.

After his big entry into the race, Perry made a series of errors from which he’s never recovered. First, he frittered away the time during which he was the center of media attention on a vapid campaign that simply relied on his Texas experience. By the time he rolled out his economic plan, he was sinking fast, he got virtually no bounce and looked more desperate than interested in (or conversant with) his own plan.

He also started out with a third-rate team that didn’t prepare him for debates, use his time wisely or set up a solid ground game in early states. By the time he realized he was being ill-served and brought in a slew of new advisers, it was too late.

The debates, of course, were disastrous. He was alternately sleepy and snippy, boastful and clueless. There was the “brain freeze” moment. There was the accusation that opponents of his immigration plan were “heartless.” And there were some really goofy foreign policy answers. But mostly he just seemed like he was in over his head.

Once all of this took its toll, the voters moved on. First it was to Herman Cain and then to Newt Gingrich. Now they seem to be dividing up among Mitt Romney, Paul and Santorum. They have never migrated back to Perry, and he’s never turned in a debate performance, generated a policy idea or put out an ad sufficiently impressive to give them reason to do so.

If, in fact, his results are poor in Iowa and his days in the race are numbered, he will return to Texas a diminished figure. His immigration policy has incurred the ire of the base. His crony capitalism and big spending on himself (on housing and travel, and now his security detail) leave a bad taste in the mouths of Tea Partyers. Fortunately for him, he won’t be on the ballot again until 2014, if he chooses to run again.

He might actually consider doing what Sarah Palin never did — hit the books, learn some public policy and restore his reputation. If he does that and is a team player (helping to elect Republicans around the country), he might have another shot at the presidency. But then again, perhaps he’s figured out that running for president is too far outside his comfort zone. One disappointing and personally humiliating run for the White House might be more than enough to satisfy his curiosity and ambition.