The two receive 46 percent support apiece in a new survey from PMI for the website Its results match what private polls have been showing: A very close race.

Sanford is seeking political resurrection in the conservative district, but has struggled to get past his past marital infidelities and recent accusations of trespassing from his ex-wife. Colbert Busch has been running a strong campaign but is struggling to overcome the district's partisan lean — Mitt Romney carried it by 18 percentage points in 2012. The election is next Tuesday.

The automated poll of 650 likely voters was conducted from April 29-May 1 and has a margin of error of plus or minus 5 percentage points.