Mitt Romney squeaked through last night with 8 vote margin over Santorum in Iowa

But at least three candidates have a plausible claim to have "won" the Iowa caucuses:

1. Mitt Romney, whose vote total of 30,015 votes exceeded that of Rick Santorum by 8 votes.

2. Rick Santorum, who rocketed from the bottom of the pack to the position of number one anyone-but-Romney candidate.

3. Ron Paul, who finished 3 percentage points behind Romney and Santorum, but whose organization reportedly instructed his well-organized supporters to stay late, and get themselves elected as delegates. Grace Wyler of Business Insider:

Paul's massive organizational push in Iowa focused on both winning votes, and also on making sure that Paul supporters  stuck around after the vote to make sure they were selected as county delegates - the first step towards being elected as a delegate to the Republican National Convention.

That's because Iowa's Republican caucuses are non-binding - they are technically just a straw poll, so once selected, delegates are free to vote for whichever presidential candidate they choose.

"Part of what we've been training the Ron Paul people to do is not to leave after the vote," Dan Godzich, a senior campaign advisor, told BI. "Stay and get elected to the conventions and get us those delegates."

Newt Gingrich only pulled in 13% of the vote, but vows to make his stand in South Carolina. Rick Perry is returning to Texas to "determine whether there is a path forward" , after receiving just over 10% of the vote, which sounds as though he may be dropping out of the race. Michele Bachmann, whose total was about half that of Perry's may not be able to continue her campaign, but vows to press on. If both drop out, presumably this would add support to Santorum.

Conservative stalwart Richard Viguerie of ConservativeHQ.com sees the results as a defeat for Mitt Romney:

"The Republican establishment is in a major panic tonight.  The Iowa caucus results show the volatility of a campaign that appears to open the door to new candidates (from the right and the center) to enter the race--all but guaranteeing the race will be settled at the Republican National Convention.

"Mitt Romney's Nelson Rockefeller-like strategy of ignoring conservatives met its limits tonight.  After five years of campaigning, and spending tens of millions dollars, Romney is almost exactly where he was in 2008--at 25% of the vote.  Romney's failure to grow his base and close the deal with conservatives tonight will undoubtedly renew the establishment's search for a new candidate to replace the flagging Romney.

Romney is expected to do well in New Hampshire, where voters are familiar with him via Boston media that reach the heavily populated southern end of the state.  Santorum's performance there will be the major question mark.  The all eyes will turn to South Carolina.

Steve McCann adds:

There are 2.1 million registered voters in Iowa.   Of that number approximately 1.4 million are registered as independents and Republicans.

Last night 122, 900 voters attended the caucus and cast their votes.   That represents 5.8% of all registered voters and 8.7% of those identified as independent and Republican.  (While theoretically a closed caucus anyone could change or register at the caucus site.)    For the record the turnout amounts to 19.0% of all registered Republicans.   (http://www.cnn.com/election/2012/primaries/state/ia)

By age group:  68% of caucus attendees were in the 45 and over group.   In the 2008 general election: 53% were in the 45 and over group.

Since 1980 only one Republican, George W. Bush, has won the Iowa caucus and gone on to win the presidency.

Richard Baher adds:

I do not see any new candidates entering the race, after being recruited by the so-called Republican establishment.  The  candidates who might have excited more Republican voters- Paul Ryan, Mike Pence, Chris Christie, Jeb Bush, just did not and do not have the fire in the belly to run this cycle.   If Obama wins in 2012, they will be around  in 2016. Most worrying is the modest turnout last night- 122,000, about the same as in 2008, when GOP race was overshadowed by Obama-Clinton-Edwards fight in Iowa  on the Democratic side. Most independents attended Democratic caucuses in 2008. Most of the independents who voted in GOP caucuses last night were new to the caucus process, and young Ron Paul voters, who likely will not back any GOP nominee other than Paul.

Romney will  win easily in  New Hampshire, though both Huntsman and Gingrich will fire away at him this week. Paul will do very well in New Hampshire- many more libertarians than in Iowa, and an open primary to welcome them if they are not Republicans. . . South Carolina will be a three way fight now- Romney, Gingrich and Santorum.   Romney could do OK there, if the other two split the more conservative vote. McCain won the state in 2008, when Romney, Huckabee and Fred Thompson divided up the conservative vote.   Taking a longer view, the new delegate selection rules will insure a longer time frame for anyone (most likely Romney ) to reach 1144.  Paul will do well in caucus states, where he has learned the Obama rules from 2008 (Obama won the nomination by beating Clinton in all but one caucus state).

The new attacks this week on Marco Rubio suggest that the left is already planning on facing a Romney Rubio ticket.

J. Robert Smith adds:

The truth is Mitt Romney lost Iowa.  Romney's presidential candidacy stretches back well before 2008.  Romney's been stumping Iowa and spending lots of cash there for over four years.  Still, Romney could only manage 25% of the vote, which is what he accomplished against the GOP field in '08. 

Romney's failure to breakout doesn't mean that he can't secure the Republican presidential nomination, he can.  A healthy campaign war chest and unsexy but critical field organizations are Romney advantages.  Still, Romney had those two advantages working for him in Iowa, and nearly out of nowhere, an under-resourced Rick Santorum surged to a virtual tie with the better provisioned and armed former Massachusetts governor. 

Romney's real edge is that conservative voters remain fractured.  Would Rick Perry's and Michele Bachmann's voters have gone to Santorum had the two quit Iowa?  Many of Perry's and Bachmann's voters would have done so, given that Santorum was the logical choice for conservative voters.  (Newt Gingrich, always vulnerable, saw his fortunes flag after spending days on end in the GOP establishment and the mainstream media meat grinders.)

New Hampshire is next, and it looks like a Romney win.  After all, the New Hampshire primary is just a week away, hardly enough time for Santorum to technically change the dynamics there.  Romney's Massachusetts is cheek and jowl to New Hampshire; the state boasts a large Massachusetts expatriate population.  New Hampshire's primary is closed, meaning independents and Democrats can't wander over to the GOP side to make mischief.  New Hampshire should be Romney stomping grounds. 

But New Hampshire - like Iowa, though more so - isn't about Romney winning; it's about expectations.  If Romney doesn't have a substantial victory in New Hampshire (an outright majority of the votes), then the perception of Romney's viability could be further damaged.

After Romney-friendly New Hampshire, come South Carolina and Florida, notably.  South Carolina is red meat conservative country, and the Sunshine State has large conservative voter segments.  If Santorum places well in New Hampshire, he'll appear all the more viable to southern conservatives anxious to nominate an A.B.M. (Anybody But Mitt) candidate. 

Expect Romney to unlimber his big guns against Santorum immediately.  Santorum accomplished in Iowa what Romney's other challengers hadn't yet accomplished.  Santorum collected real votes in a real ballot test and fought Romney to a dead heat.

As a sixteen-year congressman and U.S. senator, Santorum made plenty votes, some of which are exploitable for being un-conservative (Santorum had a taste for earmarks and Big Labor).  Romney needs to knockdown Santorum as quickly as possible - and he needs to hope that Perry and Bachmann stay in the race longer.  (Gingrich will stay in because the presidential contest is Newt's last hurrah).