Republican Tom Cotton unseats Sen. Mark Pryor in Arkansas

LITTLE ROCK, Ark., Oct. 31 (UPI) -- Republican U.S. Rep. Tom Cotton defeated two-term Sen. Mark Pryor in Arkansas.

NBC News called the race as Cotton took 56.7 percent of the vote with 50 percent of the votes counted.

Cotton's campaign portrayed Pryor as a rubber stamp for the Obama administration, closely tying the incumbent to the Affordable Care Act in the historically Republican state.

The campaign first got heated in April, when Pryor, a two-term Democrat, publicly accused Cotton of feeling "entitled" to a Senate seat for serving in the military.

The assertion failed to resonate with voters and as Arkansas voters got to know Cotton better, once-frontrunner Prior found himself chasing Cotton's increasing popularity.