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The Republican presidential contest is a two-man race no more.

Rick Santorum proved that the 2012 primary election still has a few surprises left, after he went three for three in Tuesday’s contests and once again shook up the GOP nomination battle.

Santorum, in perhaps the biggest upset of the night, was declared the winner of the Colorado caucuses -- a contest Mitt Romney had been leading in recent polls and won in the 2008 race. The former Pennsylvania senator also won the Minnesota caucuses and the non-binding Missouri GOP primary.

The candidates head next into Maine, and later in the month to Arizona and Michigan. Santorum’s performance stokes questions about Romney’s appeal in some corners of the Republican Party but also puts the pressure on Newt Gingrich – as he challenges Santorum’s claim to be the “conservative” alternative to Romney.

Santorum, though, said Tuesday night in Missouri that he wasn’t looking to be the alternative to Romney.

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"I stand here to be the conservative alternative to Barack Obama,” Santorum said.

The three-for-three finish marked the best night of Santorum's campaign since Iowa, in which he was belatedly declared the winner.

Santorum said at his victory rally in Missouri that the night's results showed conservatism is "alive and well." Santorum used the victories to build his case that the Republicans need a nominee who can demonstrate "sharp contrasts" with President Obama -- something he claims the other candidates cannot do.

Santorum went after Romney, accusing him of holding the "same positions" as the president on several issues, but largely glossed over the other GOP candidates in his remarks.

Romney is still ahead in the delegate count, despite Santorum's big night. But Santorum's victories disrupt the narrative that the GOP presidential contest had become a two-person race between Gingrich and Romney.

With all precincts reporting in Colorado, Santorum led with 40 percent of the vote. Romney was in second with 35 percent, followed by Gingrich and Paul.

With 95 percent of precincts reporting in Minnesota, Santorum led with 45 percent. Ron Paul was pulling in second with 27 percent, followed by Romney and Gingrich.

A total of 70 delegates are up for grabs in those two states Tuesday, though the caucuses are just the start of a lengthy delegate-allocating process.

In Missouri, the primary is effectively a statewide straw poll, as it sets the stage for the delegate-awarding caucuses a month from now. Still, more than 240,000 people voted in the contest, and Santorum cruised to a crushing victory. With all precincts reporting, Santorum had 55 percent of the vote. Romney had 25 percent, followed by Paul with 12 percent. Gingrich was not on the ballot in that contest.

Turnout in the caucus states was smaller. About 66,000 showed up in Colorado; turnout in Minnesota appeared slightly lower.

Gingrich, though, hardly competed in any of the three states Tuesday, instead focusing his attention on other contests down the primary calendar. He campaigned Tuesday in Ohio, which holds its election on March 6, "Super Tuesday," as the other candidates made last-minute appeals in Colorado and Minnesota.

Romney acknowledged at his rally in Colorado that Santorum had a "good night." He went on to define himself as the only candidate, though, who has never been "compromised" by the culture of Washington. And he said he still expects to be the nominee.

"This is a time for real change in Washington -- fundamental, bold, dramatic change," Romney said.

At his post-election rally in Minnesota, Paul touted his second-place finish in the state while predicting his campaign will do well in the delegate battle -- despite the fact Paul has not yet won a primary contest.

Tuesday's contests were the first of the season in which multiple states were holding contests on one day. Up next, Maine concludes its caucuses this Saturday, and primaries will be held in Michigan and Arizona later in the month.

Romney so far has won three contests, in New Hampshire, Florida and Nevada. Gingrich has won one, in South Carolina.

Romney entered Tuesday's competition with a healthy lead in the delegate count -- at 101 delegates.

Gingrich trailed with 32 delegates, following by Santorum with 17 and Paul with nine. It takes 1,144 delegates to win the nomination.

Though Missouri's primary Tuesday was largely symbolic, the contest was still expected to cost state taxpayers about $6 million.