Ron Paul is at 20%, Mitt Romney at 19%, and Rick Santorum at 18%. Rounding out the field are Newt Gingrich at 14%, Rick Perry at 10%, Michele Bachmann at 8%, Jon Huntsman at 4%, and Buddy Roemer at 2%, as reported by The Weekly Standard.

The momentum in the race is completely on Santorum's side. He's moved up 8 points since a PPP poll earlier in the week, while no one else has seen more than a one point gain in their support. Among voters who say they decided who to vote for in the last seven days he leads Romney 29-17 with Paul and Gingrich both at 13.

Santorum's net favorability of 60/30 makes him easily the most popular candidate in the field. No one else's favorability exceeds 52%. He may also have more room to grow in the final 48 hours of the campaign than the other front runners: 14% of voters say he's their second choice to 11% for Romney and only 8% for Paul.

Santorum's taken the lead with two key groups of Republican voters: with Tea Partiers he's at 23% to 18% for Gingrich, 16% for Paul, 15% for Bachmann, and only 12% for Romney. And with Evangelicals he's at 24% to 16% for Gingrich, and 15% for Paul and Romney.

Other than Santorum's rise the other big story of this week is Paul's fall. He was at 24% earlier in the week but has dropped to 20%. That decline in support coincides with a precipitous drop in his favorability numbers. On our last poll he was at +13 (53/40), but that's gone down 21 points on the margin to -8 (43/51).