* Mitt Romney didn’t win Iowa. Is he still “inevitable”? This is a big deal in more ways than one: The Des Moines Register is reporting that after a recount, Rick Santorum actually leads Mitt Romney in Iowa by 34 votes — but still-missing precincts mean the outcome will never be resolved, making it a split decision.

Many commentators saw Romney’s seeming victories in the first two states — which was hailed as unprecedented — as a clear sign of Romney’s inevitability in the GOP nomination process and of his strength as a general election candidate. It remains to be seen whether they’ll revisit that assessment now, but among Republicans, this could chip away at the sense that Romney is — or should be — the pre-certified GOP nominee, particularly as it comes after an awful political week for him.

In one sense this is moot, because Santorum faded after his surprise showing in Iowa and has yet to revive. But Romney’s GOP rivals are certain to seize on this latest news in an effort to alter the outcome in South Carolina, and it could embolden conservatives who are already worried about Romney’s strength as a general election candidate to coalesce around an alternative.

Update: CNN is reporting that Rick Perry is dropping out of the race today, raising the possibility that conservatives could begin to unite around someone to stop Romney, just in time for the South Carolina voting. Previously, Romney had been benefitting in a big way from the split conservative vote.

* Romney rolls out new response as offshoring story gains momentum: The tale of Romney’s investments in the Cayman Islands is snowballing, and the Associated Press gets a new explanation from the Romney campaign:

Neither Romney nor his campaign are providing details, including how much he has invested there, or why, or if any of his money is invested elsewhere outside the United States.

“Gov. and Mrs. Romney’s assets are managed on a blind basis. They do not control the investment of these assets,” campaign spokeswoman Andrea Saul said in an emailed response to questions Wednesday night. Romney has not personally addressed the issue, although it’s likely to come up at a candidates’ debate Thursday night.

If the Romney campaign is really going to refuse to provide details about these investments, it seems likely that the pressure will only mount on him, as his rivals on both sides will seize on this as the latest evidence that he’s not being forthcoming. And at some point — perhaps tonight — Romney himself will have to respond to questions about this. This story has taken on a drip-drip-drip quality that will continue to stoke the curiosity of the big news orgs and lead to more and more revelations.

As I've been saying, Dems will use this ongoing tale to paint Romney as a walking embodiment of everything that’s unfair about our tax system and of the ways our economic system is rigged against the middle class in favor of the rich.

* Romney’s wealth a hurdle to his candidacy: Relatedly, the New York Times goes big with a deeply reported front page piece on the “hurdle” Romney’s wealth and taxes present to his candidacy — exactly the sort of article campaign operatives dread.

* Editorial boards hammer Romney over tax returns: Both the Post and the Times unload on Romney this morning. The Post editorial calls on Romney to release returns going back many years, as Obama has, and adds that he should release the names of his major bundlers in the process.

The Times editorial, meanwhile, notes that Obama, unlike Romney, has called for closing the “carried interest” loophole, and makes the key point that “Romney has reminded Americans of the fundamental unfairness of the current tax code and of how determined Mr. Romney and his party are to keep it that way.”

* Obama campaign airs its first ad: The campaign’s first ad, it turns out, is a response to an attack ad campaign launched the other day by the Koch-funded Americans for Prosperity, which hits Obama over the failed green energy firm Solyndra:

This choice of topics — which is relatively under the radar, compared to the GOP candidates’ attacks on Obama’s economic record — suggests that the Obama team thinks the Solyndra attacks have more potency than you might have thought. Republicans hope the Solyndra story — and the ongoing attacks on “crony capitalism” — come across to swing voters as dirty government-as-usual, muddying Obama’s message that green energy is about jobs and the middle class.

Either way, the ad — which is running in six swing states — shows that Obama campaign will respond aggressively and directly even to assaults funded by outside groups.

* Newt presses case in South Carolina: He’s up with an absolutely brutal new ad featuring footage of leading Republicans describing Romney as a desperate flip-flopper and dirty campaigner.

Also: Gingrich is releasing his own tax returns today, teeing up the issue for tonight’s debate.

* Newt-mentum? A new Politico poll finds Gingrich within seven points of Romney in South Carolina, 37-30. And there’s this:

Gingrich has momentum: When voters are asked to volunteer the name of the candidate they plan to vote for without being prompted by a list of names to choose from, Romney’s lead over Gingrich slips to 31 percent to 29 percent. Among those who say they will “definitely” support their candidate of choice, the two are essentially tied, with Romney at 23 percent and Gingrich at 22 percent.

* New numbers on the economy: Breaking from the AP: “Weekly unemployment benefit applications sink to 352,000, fewest in nearly 4 years.” Steve Benen has it in chart form.

* DNC presses case on tax returns: In advance of tonight’s GOP debate, DNC spokesman Brad Woodhouse is out with a new memo pressing reporters to insist that Mitt Romney release his tax returns, arguing that he doesn’t want to reveal details of his offshoring.

Dems like this story because it feeds two key arguments they are making: That Romney is the candidate of the “one percent” and that he isn’t being forthcoming about who he is.

* The myth of right wing “populism”: E.J. Dionne on the ways the likely nomination of a private equity specialist unmasks the pretense of “populism” driving Tea Party Republicanism.

* And more than one-forth think Obama’s policies are “socialist”: A wonderful finding buried in the new New York Times poll:

How would you mainly describe the policies Barack Obama has pursued as president — socialist, liberal, moderate, conservative or libertarian?

Socialist 26

Liberal 22

Moderate 28

Obviously you can get one-fourth of the electorate to say anything, but this seems particularly interesting. Perhaps it reflects the fact that at this point it’s accepted as merely part of the game when Romney argues that Obama favors “equal outcomes” or when other GOPers call him a socialist, with media figures rarely if ever pointing out how detached from reality this really is.

Special bonus poll finding: 33 percent have a “positive” view of socialism!

What else?