Primary Hat Trick: Romney Wins Maryland, D.C. and Wisconsin

With wins in Maryland, Wisconsin and Washington, D.C., Mitt Romney inched his way forward toward becoming the inevitable GOP presidential candidate.

After Tuesday's hat trick, the road to victory is clear for Romney and increasingly rocky and unlikely for Rick Santorum, Romney's leading opponent.

Still, in a speech from Mars, Pa., Santorum vowed to continue his campaign.

"We have now reached the point where it's half time," Santorum said. "Who's ready to charge out of the locker room for a strong second half in Pennsylvania?"

The next contests happen April 24, when Connecticut, Delaware, New York, Rhode Island and Pennsylvania head to the polls. Pennsylvania is critical for Santorum, because it is his home state and a loss there would be seen as nothing short of devastating for his campaign.

In his victory speech, Romney gave no indication that his candidacy was being challenged. Romney ignored Santorum. Instead, he seemed to be shifting into general election mode, carefully drawing distinctions between himself and President Obama.

He painted Obama as a proponent of a "government-centered society." And he painted himself as a proponent of free enterprise.

"Washington should be an ally of business," Romney said, "not in opposition of business."

Romney made the argument that he's not trying to "transform" America, instead he wants to "restore" it to an America of small government with "strict limits."

Add to that President Obama's speech assaulting the Republican budget passed by the House and his campaign ads referring to Romney by name, and the campaign for president felt well underway.