Rep. Tom CottonTom CottonCruz offers bill to weaken labor board's power Overnight Finance: GOP offers measure to repeal arbitration rule | Feds fine Exxon M for Russian sanctions violations | Senate panel sticks with 2017 funding levels for budget | Trump tax nominee advances | Trump unveils first reg agenda Iran deal faces uncertain future under Trump MORE (R-Ark.) leads Sen. Mark PryorMark PryorMedicaid rollback looms for GOP senators in 2020 Cotton pitches anti-Democrat message to SC delegation Ex-Sen. Kay Hagan joins lobby firm MORE (D-Ark.), according to a new poll conducted for the Republican-aligned group American Crossroads.

Cotton leads Pryor by 46 percent to 41 percent in the poll, conducted by GOP pollster Public Opinion Strategies.

Pryor remains relatively popular in the red state — 45 percent have a favorable opinion of him, while 36 percent view him unfavorably. But in this poll, like all others in the state, President Obama's unpopularity is dragging him down. Obama's approval rating is 35 percent in the state.

Recent nonpartisan surveys have found Pryor with a lead in the race.

Crossroads is also out with a new ad attacking Pryor, part of more than $3 million in recent spending from outside groups attacking Pryor and propping up Cotton.

In the ad, a spelling bee contestant is asked to spell Pryor. After judges define him as a "Washington liberal" and say he was the "deciding vote for ObamaCare," the young girl spells Pryor "O-B-A-M-A."

The live-caller poll of 500 likely voters was conducted from May 27-29 and has a margin of error of plus or minus 4.39 percentage points.