Democratic Congressman Mike Ross will retire after his term is up. Ross, from Arkansas' 4th Congressional district, has won easily (by 18% in 2010) in an increasingly Republican district. Charles Cook rates Arkansas 4 as Republican +7. The district went for McCain over Obama by 3 to 2 in 2008.
This open seat race leans to the GOP in 2012, as Arkansas has voted strongly for the GOP in the last 3 Presidential election years. Ross, who is the only remaining Democrat in Arkansas' U.S. House delegation, may run for Governor in 2014.