WASHINGTON -- Rick Santorum has delivered a stinging blow to front-runner Mitt Romney, winning political caucuses in Colorado and Minnesota in the race for the GOP presidential nomination. Santorum also won a non-binding primary in Missouri that gave him some bragging rights but no delegates.
Santorum's three-state sweep Tuesday raised fresh doubts about Romney's ability to win over conservative voters. And it gave Santorum grounds for claiming that he -- not Newt Gingrich -- is the strongest conservative alternative to Romney.