A series of favorable polls for Democrat Mark Pryor, chairman of the Senate Appropriations subcommittee on agriculture, prompted Sabato’s Crystal Ball to rate the race as a toss-up. Until now, it viewed the race as “leans Republican.” Said the new edition of Crystal Ball, “It’s become clear over the past few months that Sen. Mark Pryor (D-AR), despite the increasing Republican lean of his state, has been holding his own, or better, against Rep. Tom Cotton (R, AR-4).”
Incumbency is worth a few percentage points in a Senate election, says FiveThirtyEight. “In the closest races…incumbency may very well turn a loser into a winner.” It features the Arkansas race, and several other Senate races to show how support for a candidate can be affected by the popularity of the president and by incumbency.