Big Win for Santorum

Santorum's victories in Missouri, Minnesota, and Colorado provide a big boost for his campaign.  Romney had lowered expectations for last night, but the size of his losses (and his loss itself and Colorado) were a blow to the campaign.

Newt Gingrich, however, may have been the biggest loser last night.  Now, there is no incentive for Santorum to drop out, and Gingrich's claim to be the leading alternative to Romney is considerably weakened.