The outcome of the Iowa caucuses, it is fair to say, is entirely unpredictable. There are a ton of polls, most of which have little or no track record of accurately gauging the results. Meanwhile, Herman Cain’s approval rating is nose-diving, Texas Gov. Rick Perry is hoping to save himself from political annihilation with a rabid immigration exclusionist’s backing, and some insiders are seeing an opportunity for a major upset.

Let’s start with Cain. The Des Moines Register tell Iowans: “Minutes after Herman Cain said he was reassessing his campaign after an allegation of a 13-year affair, some of his Iowa supporters said they were doing the same with two candidates in their periphery: Mitt Romney and Newt Gingrich.” Backing a candidate who can’t decide whether to stay in the race surely seems like a wasted vote. So watch him disappear (actually or virtually) from the race.

Meanwhile, Perry is trying to breathe life into his moribund campaign by chucking overboard his moderate approach to illegal immigration. He’s rounded up Arizona sheriff Joe Arpaio, one of the key supporters behind Arizona’s immigration bill (one that Perry said wasn’t for Texas) and a man dogged by ethics and competence issues, one that Perry said wasn’t for Texas. Arpaio is about as far as you can get from the Rick Perry who avoided incendiary rhetoric, extended tuition breaks to children of illegal aliens and showed interest at one time in the Bush comprehensive immigration plan. The Christian Science Monitor explains:

For those not familiar with the Arizona lawman, Sheriff Arpaio has built up a reputation as perhaps the nation’s the fiercest anti-illegal immigration crusader, rounding up thousands of undocumented workers in Maricopa County for deportation. And Texas Governor Perry? He has said he supports tuition breaks for illegal immigrants. . . .

And while it helps Perry move rightward on the issue, Arpaio is hardly uncontroversial — even among Republicans.

Which has a number of people questioning Perry’s decision. “Memo to Perry (and Romney, for that matter): A hard-line, anti-immigrant position is not especially popular in New Hampshire, even among likely Republican primary voters,” writes former New Hampshire GOP Chairman Fergus Cullen in a Tuesday column. Just a few months ago, he notes, 42 percent of likely Republican primary voters indicated in a survey that they supported a path to citizenship.

And in the Atlantic, Andrew Cohen wonders why anyone would want Arpaio’s endorsement. “That the beleaguered Perry would think that Arpaio will help rescue his flailing campaign is just one of the many mind-bending absurdities of the 2012 race,” Cohen writes, noting the litigations and reports of fiscal malfeasance that have dogged Arpaio’s career.

The fact that reports were surfacing Tuesday of Arpaio being booed at his town hall appearances with Perry, then, is not particularly surprising.

So much for the one issue on which Perry has shown political courage.

And then there is the potential for a dark horse to move up. In the wake of Herman Cain’s potential departure from the race I asked Craig Robinson of the Iowan Republican who could benefit. He responded, “Right now the conservative vote in Iowa is being cut up four or five different ways. With Cain out of the picture it creates an opportunity for one of the candidates stuck at 5 or 6 percent in the Iowa polls some room to group, which would also create momentum.” Who can best capi­tal­ize on this? He told me: “The person I think it helps the most is [Rick] Santorum. Unlike Bachmann and Perry, Santorum has not seen his poll numbers plummet; his problem is growth. That tells me that Cain’s supporters probably have already made a decision not to support Bachmann and Perry back in the summer. Meanwhile, they might not have given much consideration to Santorum.” He also thinks Santorum is not weighed down on the immigration issue as Perry and Newt Gingrich have been. One more factor in Santorum’s favor, he says is that “Santorum has also proven himself to be knowledgeable and capable debater, [and] if Cain is not on the stage, that gives him a greater opportunity to impress people in the debates.” Even if Cain doesn’t actually drop out, moderators may be less inclined to spend time querying a candidate going from high to low single digits.

All that says is that the race is in flux. And while social conservatives haven’t lined up behind a single candidate (Iowa Faith & Freedom Coalition and Iowa Right to Life, according to the Register, won’t endorse anyone), Romney is returning more frequently to the state and will have the chance to impress voters with appearance in debates on Dec. 10 and 15. Without anyone else in the center or moderate wing of the party, Romney figures to make a solid showing.

But right now it’s really anyone’s guess who is going to win or occupy the top few spots. If most of politics is the art of exceeding expectations, you have to figure Gingrich has the most to lose, while Romney, Santorum and maybe Bachmann could be part of the mandatory “surprise” storyline that goes with every Iowa presidential caucus post-mortem.