Obama campaign contemplates ascendent Santorum

The Obama campaign is digging deeper into Rick Santorum's record, preparing for a potential recalibration of their laser-like focus on Mitt Romney.

After months of campaign advisers and surrogates aiming their fire solely at Romney - who they cast both as a Wall Street sympathizer and a serial flip-flopper - the first signs of a shift to Santorum are emerging.

This week, the Obama campaign's Pennsylvania state director, Bill Hyers, sent an email to state supporters pointing out that Santorum "bragged that he was a tea partier before there was a Tea Party." He called Santorum's views "as out of touch as they are memorable."

The email invited Pennsylvanians to "share their recollections of Rick Santorum's record."

One campaign official said in light of the current state of the race, the Obama campaign has to be prepared.

"Given that Sen. Santorum has won more states than Gov. Romney, it would be political malpractice not to adjust our strategy to take [Santorum] into account," said the official.

Another campaign official says there is no shift in the ultimate expectation that Romney will be the eventual nominee, however. Still, the official said, Santorum's wins in Colorado, Missouri and Minnesota, have them "paying attention."