This is a bit far afield for the typical things we highlight on this blog. However, we thought this was an interesting story. Both Tom Schaller (538.com) and John Sides (The Monkey Cage) offer good initial analysis of the outcome. The other three references are simply offered for those seeking background information on the controversy.
Something Fishy in the South Carolina Primary (Tom Schaller @ 538.com),
Did Alvin Greene Win Because of Ballot Order? Because of Race? (John Sides @ The Monkey Cage)