ABC's Tahman Bradley Reports from Washington

Rick Santorum makes a huge comeback this morning, dominating Republican contests in three states.

Mitt Romney is left licking his wounds, desperate for better luck later this month with primaries in Arizona and Michigan.

The former senator may have breathed new life into his push for the GOP nomination with victories in the Colorado and Minnesota caucuses and
the Missouri primary.

Rick Santorum said, "I don't stand here to claim to be the conservative alternative to Mitt Romney.  I stand here to be the conservative alternative to Barack Obama.

Santorum used his victory speech to unload on President Obama, who he said is not listening to the American people.

Santorum said, "Has he ever listened to the voice of the Americans before? No.  Why? Cuz he thinks he knows better."

Tuesday was a punch in the gut for Mitt Romney.  The results raise fresh questions about the former Massachusetts governor's ability to win conservatives.  This Minnesota voter talked about why she supported Santorum.

It's Republican base voters like this that rebuked Romney in Tuesday's contests.

Mitt Romney said, "This was a good night for Rick Santorum.  We'll keep on campaigning down the road.  But I expect to become our nominee with your help."

Santorum's huge night could also be a blow to Newt Gingrich.  The former Speaker is trying to hold onto his spot as the chief alternative to Romney.

Romney performed much worse in all three states compared to when he ran four years ago.

In 2008, Romney won 60 percent of the vote in Colorado and grabbed Minnesota by 18 points.