Hoo boy.... The Republican presidential contest just keeps getting more interesting.

Public Policy Polling is reporting that Rick Santorum led Mitt Romney by 15 points in a survey conducted February 9 and 10.

I'm not making too much of that; it's just one poll, and according to Real Clear Politics, a Gallup poll conducted February 7 through 11 showed Romney ahead by 7 points.

Still, the RCP chart showing candidates' movement over the past year carries a bit of a warning sign for Romney. Except for a few-day drop when Newt Gingrich temporarily peaked in late January, Romney's been climbing steadily since early December. But Gingrich has been tanking, and as he has done so, Santorum has been climbing sharply.

The RCP poll average still has Romney ahead of Santorum by 5.8 points. Santorum may just have a chance, though. He's way behind in fund-raising. But over the weekend, Sarah Palin inserted herself back into the limelight, wowing the crowd at the Conservative gathering and then saying on Fox News on Sunday that she's "not convinced" that Romney is what conservatives or Republicans need.

The Hill relays this Palin quote: "Our candidate must be someone who can instinctively turn right to constitutional, conservative principles," Palin said Saturday. "It's too late in the game to teach it or to spin it at this point. It's either there or it isn't."

Clearly, conservative Republicans are not going to let Romney walk away with the nomination. Whether they have the numbers and the money to keep him from getting it at all is still questionable, I think.

We may not find out until the party's convention this summer. We'll know a lot more, though, on Super Tuesday, which is now less than a month away.