Santorum sweeps; wins in Missouri, Minnesota and Colorado

» View our political blog, with live updates and analysis of each primary.

WASHINGTON — A resurgent Rick Santorum won Minnesota's Republican presidential caucuses with ease Tuesday night and was declared the victor in Colorado as well, a stunning sweep that raised fresh questions about front-runner Mitt Romney's appeal among the ardent conservatives at the core of the party's political base.

Santorum triumphed, as well, in a nonbinding Missouri primary that was worth bragging rights but no delegates.

"Conservatism is alive and well in Missouri and Minnesota," the jubilant former Pennsylvania senator told cheering supporters in St. Charles, Mo. Challenging both his GOP rival and the Democratic president, he declared that on issues ranging from health care to "Wall Street bailouts, Mitt Romney has the same positions as Barack Obama."

Romney, a former Massachusetts governor, was expected to remain the front-runner for the GOP nomination nevertheless, thanks to his huge advantages in campaign cash and organization going forward, and his impressive earlier wins in New Hampshire, Florida and Nevada.

Still, the solid Santorum vote provided fresh evidence that "Romney's is a troubled candidacy," said Lawrence Jacobs, a professor of political science at the University of Minnesota. "The outcome of the race is far from certain."

The strong showing by Santorum made it clear that Romney isn't yet his party's consensus nominee. It signaled that the GOP nomination campaign may remain a bitter struggle for months, possibly leading to a divided August convention and a weakened candidate against President Barack Obama in the fall.

In Minnesota's caucuses, with 83 percent of precincts reporting, Santorum, a former U.S. senator from Pennsylvania, had 45 percent. Texas Rep. Ron Paul had 27 percent, and Romney trailed with 17 percent. Newt Gingrich, former Speaker of the House of Representatives, had 11 percent. Romney won the Minnesota GOP caucuses in 2008.

In Missouri, a crucial swing state in the November elections, Santorum was headed for a landslide. With 99 percent of precincts reporting, he had 55 percent to Romney's 25 percent. Paul had 12 percent. Gingrich was not on the ballot; 4 percent were uncommitted.

The Missouri vote was a non-binding "beauty contest," since no delegates were at stake and candidates made little effort to campaign there. But Santorum's victory gave his campaign renewed momentum.

Santorum, speaking to supporters in St. Charles, Mo., contrasted himself to Obama.