Even the political pros were shocked last week by Rick Santorum’s sweep of Tuesday’s primary elections.  While many of the prevailing attitudes still favor former Massachusetts Gov. Mitt Romney to take the nomination, many within the Republican party, especially social conservatives, are taking a serious look at the former senator from Pennsylvania as a desirable alternative to Romney.

Mitt Romney is still a party favorite and often called the most likely to beat Obama, but he has also retained an undeniable enthusiasm gap between his supporters and those of Ron Paul and other nomination-seekers who have experienced dramatic rises and falls during the last year’s tumultuous primary campaign.

According to a Republican political consultant involved in the nomination battle, Romney has had a fairly good week since delivering a decisive win in Maine and is looking forward to a likely victory in Arizona next Tuesday. 

However, the Maine caucus garnered little national media attention, due to the unsurprising final tally and miniscule delegate count.  Most attention has been turned to the rust belt state of Michigan, where the two leading candidates are currently polling in a tie.

The Republican source, who asked not to be named, pointed to Florida as the true turning point for the Santorum campaign.  Forced into the defensive by a shower of attack ads and the Romney campaign’s vastly dominant war chest, Gingrich was unable to deflect the considerable baggage from his personal life as he did in South Carolina the week before. 

After an unsurprising Romney win in Nevada, the campaigns moved westward to Missouri, Minnesota and Colorado, where Santorum began to hone his popular message comparing Romney’s health care plan with that of Obama’s. 

With his Iowa victory official on the day of the South Carolina primary, Santorum found a sweet spot in the candidate short list, sitting just far enough below the surface of the increasingly bitter Romney-Gingrich rivalry to avoid sustained national scrutiny, yet significant enough to seem viable in the minds of primary voters.

With Gingrich suddenly all but finished, that dynamic has certainly disappeared.  Colorado was the most significant primary last week, where Santorum took county after county in a rout that few had seen coming. 

Across the state, counties that in 2008 had delivered Romney 60-70 percent victories over John McCain, were yielding victories of only 10-20 percent.

The story thus far has seen Romney’s campaign repeatedly growing overconfident in his chances of victory and refocusing attacks at President Obama, only to have their “inevitability” cushion pulled from under them by the next challenger. 

As the battle for Michigan intensifies, Santorum will be tested for the first time as a legitimate candidate for the nomination.  With Gingrich’s campaign back on life support, it would be a long uphill battle for him, but if recent history serves as a guide, not an impossible one.  Even so, many see the key for Santorum to be whether Gingrich steps down. Without such a twist, the Pennsylvanian could end up losing his momentum and be forced to continue splitting the “anyone but Romney” vote.