Last night when discussing the trends in the three non-binding Republican contests, I tweeted that Rick Santorum’s win in Missouri was only surprising in gaining a majority, but that a win in Minnesota would be surprising — and a win in Colorado would be shocking.  As it happens, National Journal agrees with that assessment. Santorum shocked the Republican race with a clean sweep of Tuesday’s caucuses and primary, and may have pushed himself into serious consideration as the long-sought conservative consolidation alternative to Mitt Romney:

Rick Santorum on Tuesday completed his sweep of states with a stunning upset of Mitt Romney in Colorado’s caucus, according to state Republican officials, shaking up a GOP presidential race that has seen more drama than Romney’s campaign envisioned even a week ago.

Santorum earlier won Minnesota’s caucus and a non-binding Missouri primary. Romney – who won Colorado handily in 2008 — had long remained the odds-on favorite to prevail in that state’s caucus, as polls had shown him with a double-digit lead.

A jubilant Santorum told supporters that he isn’t the conservative alternative to Mitt Romney:

“I don’t stand here to claim to be the conservative alternative to Mitt Romney,” he told supporters earlier in the evening. “I stand here to be the conservative alternative to Barack Obama.”

Missouri had looked for some time to be Santorum’s best shot.  Newt Gingrich chose not to get on the ballot, which made the state Santorum’s opportunity to fight Romney head-to-head.  What little polling existed showed Romney to be about ten to twelve points back, but Romney ended up losing by thirty points as Santorum claimed a 55% majority.  Santorum swept every county, including the presumed Romney stronghold of St. Louis, putting an exclamation point on Santorum’s ability to beat Romney.  He also beat Ron Paul in Minnesota by eighteen and Romney by 28, a state Romney carried easily in 2008, but with a low turnout in 2012 despite appearances from both candidates in the final few days.

However, while Santorum was expected to be competitive in Minnesota, Romney was widely expected to win Colorado.  Romney stayed in Denver for the caucus results, which differed sharply from his massive 42-point 2008 victory.  Instead, Romney ended up the night down five points in a race that also had a 10% dropoff in turnout from four years earlier.  Suddenly, Romney’s organization and his ability to simultaneously compete in multiple states looks a lot less formidable than it did a week ago, and this three-state loss — especially in Minnesota, where Romney finished third behind Ron Paul — makes Romney look a lot less inevitable.

It wasn’t all that good of a night for Paul, either, though.  He managed to get into second place in Minnesota thanks to Romney’s stumble, but Paul was supposed to own the caucus states through his superior organization and fundraising.  His strategy was to win smaller-state caucuses and build a delegate count that would force Republicans to bow to his movement at the convention in Tampa.  He’s getting higher percentages of the votes but not doing much better in a four-man race in position finishes than in 2008.  As in the previous contest, his support and influence is beginning to look overrated, and Paul has to hope for something better out of Maine’s caucus this Saturday.

The man who suffered the worst night was Newt Gingrich.  Gingrich’s absence from the Missouri ballot, which was a deliberate tactical move, looks like a big mistake in retrospect.  He allowed Santorum the opportunity to probe that it would be Santorum and not Gingrich who could rally conservatives against Romney.  Gingrich’s third-place finish in Colorado barely beat Paul to stay out of the cellar, and Gingrich did finish dead last in Minnesota.  There isn’t even a fig leaf of spin from these results to which Gingrich can cling; Gingrich was entirely irrelevant in all three contests, except to the extent that he got beat.

After Maine’s caucuses on Saturday, which I presume all four candidates will now hotly contest, the next big test will be to see if and how Santorum can build on his sweep in Arizona and Michigan.  Romney had big leads in both, with Santorum in third place behind Gingrich.  We’ll see whether these non-binding contests matter to voters on February 28th — and Super Tuesday on March 6th.  If nothing else, this is a very good time for a shoestring campaign to catch fire.

Update: Byron York reports that this sweep may have been ordained in Florida, thanks to the nasty, personal battle between Romney and Gingrich:

“I think this started in Florida, when Mitt Romney and Newt Gingrich went at each other with such personal attacks,” says Chuck Laudner, a longtime ally of Rick Santorum, calling late on election night from Minneapolis.  “They weren’t really on the issues.  It was investments and name calling, and I think it turned people off.  People here looked at that and said there’s got to be an alternative.”

Laudner, the Iowa conservative political operative who became nearly a household name as the owner and driver of the “Chuck truck” that carried Santorum across Iowa before that state’s caucuses, spent the last ten days in Minnesota, trying to persuade influential Republicans to support Santorum. “Ten days ago, I couldn’t get a single statehouse or senate member to go public with an endorsement,” he says.  Then, after the fighting in Florida and its continuation in Nevada, things changed.  “By the end of the week, we got a couple of endorsements, and they helped us get a couple more, and then we had a lot of names.”

The shift to Santorum was fast and overwhelming.  In the end, Santorum beat Romney by 27 points in a state Romney had won by 19 points back in 2008.  Santorum scored an even bigger victory in Missouri’s beauty-contest, nonbinding primary, beating Romney by 30 points.  And even in Colorado, where the race was closer, Santorum came out ahead.  For a candidate who hadn’t won since his narrow and belated victory in Iowa, it was three victories in one night. Santorum has now won four contests to Romney’s three and Gingrich’s one.

Speaking for myself, the Florida contest prompted my final assessment.

Update II: Santorum beat Paul in MN by 18, not Romney, whom he beat by 28.  I’ve corrected it above.

Update III: My friend Shaun Mullen wanted a little more insight into what may be going on in Minnesota  It’s important to remember that the activist conservative base drives the caucuses in Minnesota, which is why Romney won in 2008; he was seen at that time as the conservative alternative to the inevitable John McCain nomination.  Santorum has done a good job in articulating the conservative agenda while Romney and Gingrich spend their time attacking each other on Bain and Freddie Mac.  This is the consequence.