8:24 PM

Checking in on Georgia, we see Santorum is still holding on to 2nd place there. Which reminds us:

From CNN:

8:17 p.m. ET - @jimacostacnn: Santorum's Brabender: “I’ll be interested to find out if Mitt Romney has won a southern state today.”

With 8 PM looming, and Rick Santorum currently behind in Ohio, he'll be desperate for good news out of conservative Oklahoma and Tennessee. Among GOP voters, 72 and 71% respectively say identify as evangelicals there.

UPDATE 8:05 PM And . . . Fox calls Oklahoma for Santorum.

UPDATE 8;09 PM. Looking good for RS in Tennessee too, according to CNN:

CNN exit polling in Tennessee showed Santorum with 35% support, followed by Romney with 28%, Gingrich with 23% and Paul with 11%.

Okla primer from NBC:

Oklahoma (primary)
Delegates at stake: 40
Polls close: 8:00 pm ET
Open/closed: Closed (registered party members only)
Early voting: In person, no-excuse absentee voting
Mar. 2 (Fri), Mar. 3 (Sat), Mar. 5 (Mon)
Delegate allocation:
CD delegates (15). Proportional per CD vote (15%
threshold); WTA with majority
AL delegates (25).Proportional per statewide vote
(15% threshold); WTA with majority

7:50 PM

Lots to mine here in the full CNN exit poll data, but to start:

Santorum did well among blue collar voters (Romney only beat him among those making $100K+), and very conservative/tea party voters. He lost Catholic voters to Romney 43-30%.

7:37 PM

From Nate Silver at the NYT:

Georgia rules require that a candidate get at least 20 percent of the vote statewide to get proportional delegates there. (The candidate is still eligible for Congressional district delegates even if he does not meet this threshold.)

Exit polls project that this could be a close call for Mr. Santorum; they had him tracking to almost exactly 20 percent of the vote in Georgia. He is doing slightly better than that in the actual vote count so far, with 26 percent of the vote, but most of the few precincts that have reported so far are from south and central Georgia and are likely to be stronger for Mr. Santorum than the Atlanta area.