(CBS News) - The Rick Santorum bandwagon is picking up speed.
The latest Gallup tracking poll of Republican voters finds Santorum leading Mitt Romney by eight points.
Over the weekend, Santorum attacked President Obama, and the president's re-election campaign hit back.
For months, it's focused its fire on Mitt Romney -- believing he will be the Republican nominee. But over the weekend, for the first time, the president's campaign took direct aim at the new front-runner, Rick Santorum -- hitting him hard for something he didn't really even say.
Campaigning in Ohio, Santorum was criticizing the president's liberal environmental views, which he said hurt the American people.
"It's not about you,' Santorum declared."It's not about your quality of life. It's not about your jobs. It's about some phony ideal. Some phony theology. Oh, not a theology based on the Bible -- a different theology."
But many in the media reported that Santorum was somehow suggesting President Obama wasn't a Christian. And the Obama campaign, trying to typecast Santorum as an extremist, pounced.
"I can't help but think that those remarks are well over the line," Senior Obama Campaign Adviser Robert Gibbs said Sunday on "ABC This Week." "It's wrong. It's destructive."
On "Face the Nation" on CBS on Sunday, Santorum said he wasn't talking about the president's religious faith, but his liberal ideology. "I've repeatedly said I believe the president is a Christian,' Santorum remarked."He's says he's a Christian. But I am talking about his world view and the way he approaches problems in this country, and I think they're different than how most people do in America."
In the past month, Santorum has surged to the top of polls, and now even leads Romney in Michigan, the state where Romney grew up. But with front-runner status comes scrutiny, and attacks from all sides.
Former front-runner Newt Gingrich, now trailing Santorum and Romney, continues to blame his decline on the attacks directed his way, especially those by a political group supporting Romney.
Says Gingrich: "I think he's already damaged by the negativity of his campaign and the fact that he keeps driving down turnout ... and I think, for the general election, that's not a very good sign."
But now, the man-of-the-hour, Santorum, is getting huge crowds and lots of enthusiasm. Sunday night in Georgia, thousands came to hear him speak.