Former Sen. Rick Santorum's star has brightened considerably, at least for now, after caucus wins in Minnesota and Colorado and a first place finish in the non-binding Missouri Republican presidential primary.

The sweep raised fresh questions about front-runner Mitt Romney's appeal among the ardent conservatives at the core of the party's political base.

Santorum says his win shows that "Conservatism is alive and well."

Santorum won Minnesota with 45 percent support but Colorado was closer. He beat Romney 40 percent to 35 percent.

Romney showed no sign of disappointment in remarks to supporters, calling it "a good night for Rick Santorum." Romney says he still expects to be the nominee.

Ron Paul says he's still slowly building delegates and plans to be heard at the convention.

Newt Gingrich was far off the pace.