Romney will take tougher approach to Santorum, adviser says

Denver (CNN) - As Rick Santorum counted up his victories Tuesday night, a senior adviser to Mitt Romney signaled the campaign would take a tougher approach toward his resurgent rival and portray him as a Washington insider.

Santorum pulled off a stunning trio of victories in the Tuesday night voting contests, injecting his campaign with much-needed momentum as the GOP contenders looked ahead to the delegate-rich group of states that will vote March 6.

After reminding reporters that Santorum had endorsed Romney in the 2008 race, senior adviser Stuart Stevens suggested the former Massachusetts governor would begin to focus on his newly ascendant opponent on the stump.

"I think we'll see differences in approach that will be explored. Rick Santorum tonight was fairly aggressive in his contrasts, and I think we'll see differences," Stevens said of the two-term senator Tuesday night. "Look, I just don't think it's a time when people are looking to Washington to solve problems with Washington."

Santorum has passionately criticized Romney over his Massachusetts health care plan, which the former senator has said is too similar to President Barack Obama's health care plan and would cripple Romney in a fight against the president in the fall.

While the Romney campaign has focused many attacks on former House Speaker Newt Gingrich, in Iowa and New Hampshire they peppered Santorum over his defense of earmarks while in the Senate.

Tuesday was a grim night for Romney - he suffered an embarrassing defeat in Colorado, where he had predicted a win and spent two days campaigning. A modest audience of supporters did not fill the room in Denver where he gave his evening speech.

Stevens downplayed the results, pointing to Romney's blowout wins in Florida and Nevada and insisted the Romney campaign had carried out the right strategy.

"We'd like to win everywhere, but you can't," he said. "And we've focused on key states for how we see a path to the nomination."