Politics

Audie Cornish talks to NPR's Ron Elving, Ari Shapiro and David Welna about the Republican primary in Wisconsin.

Audie Cornish talks to NPR's Senior Washington Editor Ron Elving about Tuesday's primaries in Wisconsin, Maryland, and Washington, D.C.

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?"