STEVE INSKEEP, HOST:
Now let's look at how money is affecting the presidential election. One major factor in the Iowa results was likely a barrage of attack ads against one-time front-runner Newt Gingrich. The ads came from a SuperPAC supporting Mitt Romney.
SuperPACs are supposedly independent organizations, made possible by the Supreme Court's Citizens United decision in 2010 and some other election-law changes.
Here's NPR's Peter Overby.
PETER OVERBY, BYLINE: The superPAC behind former Massachusetts Governor Mitt Romney blanketed the Iowa airways with attack ads like this one.
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OVERBY: Restore Our Future spent $4 million on the ads. That meant the average Iowa TV viewer would have seen them three-dozen times per week. They were a major reason that Gingrich, the former House speaker, plummeted from first place in the polls to fourth place Tuesday night.
Restore Our Future is run by former campaign aides to Romney. But officially, it's not part of his presidential operation. There are superPACs backing all of the major candidates. They raise whatever money they can get - no limits required - from corporations and wealthy individuals.
But there hasn't been any disclosure of donors since last July, and there won't be any till the end of January. Bill Allison is editorial director for the Sunlight Foundation, a group that promotes transparency in politics.
BILL ALLISON: We have the Iowa caucuses; we have the New Hampshire, South Carolina, and Florida primaries; and we won't know who is donating to the organizations that were trying to knock those other candidates out.
OVERBY: The superPACs stay below the radar by cherry-picking disclosure requirements from the federal election laws. It's absolutely legal. But not everyone in the superPAC world agrees that secrecy is a good thing. Washington lawyer Robert Kelner advises superPACs and big donors. He says that for people giving the money, the timing of disclosure is immaterial.
ROBERT KELNER: They have already decided, when they chose to make the contribution to a superPAC, that they were comfortable with their name being in the public records.
OVERBY: As for the superPACs, he says they don't benefit from temporarily hiding a controversial donor.
KELNER: If it's that big an issue, then maybe the superPAC doesn't want that particular contribution in the first place.
OVERBY: And while candidates are usually desperate for every regulated contribution they can get, Kelner says the superPACs tend to be well-funded.
KELNER: And they can make, you know, nuanced choices as to which contributions they want to accept, and which ones they don't.
OVERBY: No one at Restore Our Future was willing to speak on the record yesterday. But C. Edmund Wright was. He's the spokesman for Winning Our Future, a superPAC run by former aides to Gingrich. Wright says transparency would have made Restore Our Future tone down its attacks.
C. EDMUND WRIGHT: Just common sense tells me that they would've given a lot less money, and maybe not been quite as negative.
OVERBY: Then again, Gingrich has now shed his nice-guy persona. And yesterday, the Winning Our Future website featured an old ad from John McCain's 2008 campaign - A Tale Of Two Mitts.
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OVERBY: It's a message that Winning Our Future would like to repeat with its own ads, financed by its own secret donors. Professor Anthony Corrado has spent years studying the flow of political money. He says Iowa gives just a hint of what's to come.
ANTHONY CORRADO: We're really turning the clock back. We will have more undisclosed money used in the presidential election than we have seen since the elections prior to Watergate.
OVERBY: And, as in Iowa, the undisclosed money stands ready to deliver the harshest attacks.
Peter Overby, NPR News, Washington.