Tuesday marks the last big day for Republican presidential candidates before a three-week lull, and a split result in the three states could keep the race heated.
On the eve of the latest contests, Mitt Romney, Newt Gingrich and Rick Santorum all visited Colorado on Monday, while Ron Paul campaigned in Minnesota. Both states will hold caucuses on Tuesday, and a primary is set in Missouri.
Other than Maine's week long caucus, which ends Saturday, nothing else is scheduled until the Arizona and Michigan primaries on Feb. 28.
Republican voters will choose 36 delegates in Colorado and 40 in Minnesota. And although those delegates are free to switch candidates before the state conventions later in the year, they're unlikely to do so. Missouri's primary has no delegate prize but is an important indicator of how well candidates will do there when delegates are apportioned in a March caucus.
At a rally in Grand Junction, Colo., and fresh off resounding victory in Nevada, Romney accused President Obama of saying one thing but doing another when it comes to energy development, an important topic in the West.
"Like natural gas and oil and coal, as well as nuclear, the president has said he's in favor of all of the above. But look at the EPA, which is in favor of none of above," Romney said. "I will have an EPA to encourage development of energy."
Romney won the Colorado caucus in 2008 and is expected to do well here again.
In Gingrich's first campaign visit to the Rocky Mountain state, he softened his recent attacks on Romney, saying he's spent time rethinking his campaign. At a grass-roots rally in Golden, he argued that his time as a lawmaker in Washington, D.C., only made him a stronger contender for the White House.
"I've seen Washington enough and done enough things with Reagan and Clinton," he said. "We have to set the stage to have a campaign this fall in which we have a team running so we can win."
The former House Speaker's strategy of concentrating on winning Southern primaries on Super Tuesday, March 6, suffered a blow with his failure to get on the Virginia ballot.
Santorum is expected to do well in Missouri's contest though it won't help him in the hunt for delegates, and Gingrich is expected to do well in Minnesota, making it possible that there will be three different winners in three different states on Tuesday night.
Colorado's Republican Party Chairman Ryan Call predicts the winner of the state's caucus will be well positioned to do well going forward.
"Colorado's electorate is pretty evenly divided. There's about a third that are registered Republican, about a third that are registered Democrat and a third that are Independent," he said. "Having a candidate that can speak to the issues and cut across party boundaries and partisan labels is very important.
"I think a candidate that does very well in Colorado will have the opportunity to win the Electoral College votes that are necessary to take control of the White House."