A few more notes:
* If anyone knows a thing or two about finishing second in a primary before winning a runoff, it’s Sanford, who did just that in his first House campaign in 1994.
* Jim DeMint, who turned an initial second-place showing into a runoff win in his 1998 House campaign, accomplished the same thing when he ran for the Senate in 2004.
* In the 2006 lieutenant governor's race, Andre Bauer won the GOP runoff after finishing second in the primary.
Of course, looking at runoff trends is only one metric. The individual characteristics of every race must be given heavier consideration, and the contours of the upcoming runoff bode pretty well for Sanford at this point. Still, it’s worth bearing in mind what a first-place finish has tended to mean.