4:04 PM PT: In addition to the SC-01 runoff, there are three state legislative special elections taking place tonight in Massachusetts, as well as the first round of the Omaha, Nebraska mayoral primary.
4:07 PM PT: Oh, and elections in Wisconsin, too, for state supreme court and some other races.
4:30 PM PT: Looks like the first trickle of votes has started, but it's just one precinct so far.
4:42 PM PT (David Jarman): We're finally getting to the point where we have enough numbers to talk about... with 2% reporting (6 out of 317 precincts), Mark Sanford is leading Curtis Bostic by a 62-38 margin. Now ordinarily, I'd say, "let's wait before drawing any conclusions," but the reason this bodes very poorly for Bostic is because 5 of those 6 precincts are in exurban Berkeley County, which along with similarly-exurban Dorchester County is where Bostic did the best in the first round. (Sanford, by contrast, did best in more urbane Charleston County.) Bostic would need to be winning Berkeley to have a hope of winning at all, but the SoCon-powered Bostic is trailing 61-39 even in the megachurch 'burbs.
4:54 PM PT (jeffmd): Aggregating the data between the AP and the SC state site, we're at 11% reporting, and Sanford's fallen to about 54% of the vote. Sanford's doing about 15% better than his 37% first round performance which, when you do the math, puts him just above 50%.
5:00 PM PT (jeffmd): Some more quick updates bring us to 18% reporting, with Sanford at 58% now. He's doing better in Berkeley (59%) than Charleston (57%), which was his strongest county last time. Regardless, Sanford's doing about 19% better than he did in the first round, which should be enough.
5:03 PM PT (jeffmd): Beaufort County suddenly reported 67 of its 80 precincts, which narrowly go for Bostic. Still, Sanford's overperforming by 19%, which is still enough.
5:06 PM PT (jeffmd): A smattering of additional precincts makes it 47% reporting. Sanford's at 54, +19.0 from the first round. He's got this one.
5:13 PM PT (jeffmd): 64% reporting now, and Sanford's crossed the decimal threshold to 55%, an improvement of +19.2 from round 1. Hard to see how Bostic pulls this out.
5:17 PM PT (jeffmd): And now, 73% reporting. Sanford is edging up enough, as his stronger areas come in, to get to 56 percent to Bostic's 44.
5:21 PM PT (jeffmd): And there's the checkmark. The AP's called the race for Mark Sanford, who will now face Democrat (and sister of Stephen) Elizabeth Colbert Busch.
Either we get one more Dem in Congress, or we get a giant PITA for John Boehner. I like the payoffs here.
9:38 PM PT: And I just want to add, PPP nailed it yet again. They were the only firm to offer a public poll of a very difficult-to-poll runoff, and they found Sanford up 13. He won on Tuesday night by 14. Hard to get much better than that.