Davis (whose path crossed slightly with mine at law school) is an African American. He lost the primary and the African American establishment endorsed his primary opponent, a white man.
Davis didn't play the race card -- in fact, he didn't openly court black votes. Clearly, and to his credit, he wasn't planning to run as the "black" candidate. This decision probably made political sense in the fraught racial atmosphere of South Carolina.
But what's remarkable is the decision of the African American establishment not to support him. It reminds me of all the "feminist" groups who will endorse men over women (among other instances, supporting liberal Illinois Senator Paul Simon over moderate Republican Lynne Martin in 1990).
It makes it clear once again that the "interest groups" really aren't about advancing a gender or race; that's all just marketing. In the end, they're just about advancing the farthest left ideology out there and promoting their own power.
Davis showed some signs of political moderation and independence. He was the only member of the Congressional Black Caucus to oppose ObamaCare (again, another good political decision for South Carolina, but still . . .). Apparently, that was too much for those in the African American establishment who care more about a leftist agenda than about supporting a credible, African American Democrat for their state's highest office -- and who took positions designed to make him competitive in a general election.
Now Davis says he's retiring from politics. Congratulations, African American interest groups. You've just run a rising star out of the arena.