The latest political polls suggest there may be some surprises left in the race to determine which Republican candidate will represent his party in the November presidential election.
The next caucuses take place Tuesday in the states of Colorado and Minnesota. The front-runner so far, former Massachusetts governor Mitt Romney, appears poised in Colorado for a repeat of his solid victory in nearby Nevada.
But in Minnesota, polls suggest any one of the four candidates could take first place, with former senator Rick Santorum currently in the lead.
And polls in both states show the former speaker of the House of Representatives, Newt Gingrich, has lost significant support. Gingrich had been considered Romney's closest rival for the nomination, and in December held a commanding lead in Colorado polls. He is now polling in third place.
Public Policy Polling, which conducted the surveys, says Santorum has been helped because no other candidates have been attacking him.
Romney has won the contests in New Hampshire, Florida, and now Nevada. He is hoping to maintain his momentum with wins Tuesday in Colorado, Minnesota, and on Saturday, in Maine.
But if Santorum can pull off a victory in Minnesota and a second place finish in Colorado, he may become Romney's biggest challenger for the nomination. Santorum is also polling well in Missouri, according to Public Policy Polling's latest survey there last week.
Gingrich is vowing to fight all the way to the nominating convention, being held in Tampa, Florida, in August.
Congressman Ron Paul also remains in the race, but is trailing behind the other three candidates.