Quinnipiac: Rick Santorum with slim Ohio lead, but Mitt Romney gaining

Quinnipiac. February 29-March 1. Ohio likely Republican primary voters. ±4.3%. (February 27 results)

Santorum: 35 (36)
Romney: 31 (29)
Gingrich: 17 (17)
Paul: 12 (11)

This poll was conducted entirely after the Arizona and Michigan primaries, so it's not surprising that Mitt Romney has closed some ground. But the poll still shows Santorum with an edge.

Quinnipiac also polled the state from February 7-12. In that survey, Santorum had 36 percent and Romney had 29 percent, identical to the February 27 results. Newt Gingrich was at 20 and Ron Paul was at 9, so each of those candidates have actually had more movement than either Santorum or Romney.

Rick Santorum continues to have the most committed voters, but compared with the February 7-12 poll, Romney has had a dramatic firming up of his support:

Is your mind made up, or do you think you might change your mind before the election? (Feb 7-12 results in parentheses.)

Rick Santorum voters:
Mind made up: 69 (54)
Might change: 30 (44)

Mitt Romney voters:
Mind made up: 65 (39)
Might change: 34 (58)

Newt Gingrich voters:
Mind made up: 50 (48)
Might change: 48 (51)

In absolute terms, there's about the same number of Santorum, Romney, and Gingrich voters up for grabs, but because Gingrich has so much less support, a bigger chunk of his voters could flip their support to one of the other candidates. Given the tightness of the race, there's plenty of room for a lead change. We probably won't have a very good handle on what's going to happen in Ohio until Sunday or Monday, as Nate Silver's analysis of primary polling shows.

There's another contest taking place over the weekend that could influence Ohio and other Super Tuesday results as well. Washington State Republicans hold their caucuses on Saturday, and according to Public Policy Polling's latest survey, Mitt Romney has moved ahead of Rick Santorum, leading 37 percent to 32 percent. Two weeks ago, PPP had Santorum leading, 38 percent to 27 percent, so the poll shows a net 16 point swing in Romney's direction. As PPP points out, however, caucuses are tough to poll, and Santorum has tended to outperform polling in caucuses thanks to his committed base of supporters.