PHOENIX -- Arizona Sen. John McCain would likely face a tough race if he were to run for reelection in 2016.
The Behavior Research Center surveyed 700 voters last month in Arizona and found 37 percent approve of McCain's performance but 33 percent gave him a thumbs down.
Nearly 40 percent of registered Republicans surveyed rated his performance as poor, up from only 27 percent last summer.
McCain hasn't announced whether he will seek a sixth-term in 2016 when he turns 80.
The new Rocky Mountain Poll said Sen. Jeff Flake may be making some modest headway with Arizonans. More than 20 percent of those surveyed rated Flake's performance "good," up from 17 percent last summer after he was found to be the nation's most unpopular senator by a Public Policy Poll.
The Rocky Mountain poll said Flake's improved stock with the public is most noticeable within the ranks of registered Republicans and Independents. Democrats remain very cool toward the senator.