Rep. Tom CottonThomas (Tom) Bryant CottonThe Hill's Morning Report - Lawsuits, investigations send Trump on Twitter tirade GOP senator: Democratic opposition to Pompeo 'driven 100 percent by politics' Sunday Shows Preview: Emmanuel Macron talks ahead of state dinner MORE (R-Ark.) is out with an internal poll showing him leading Sen. Mark PryorMark Lunsford 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.) in his race for the Senate, pushing back on recent public polling that has found Pryor ahead.

Cotton leads Pryor by 42 percent to 40 percent in the live-caller poll of likely voters by GOP pollster On Message Inc.

Most polling has found a close race in Arkansas, but two recent polls, one from NBC News/Marist that came out on Monday and the other from New York Times a few weeks back, found Pryor up by a double-digit margin. Cotton's pollster pushes back on those results, pointing out that registered voter samples often skew Democratic compared to those found in the general election.

"We have successfully weathered a constant hailstorm of negative ads and remain in excellent position to win this race," pollster Wes Anderson writes in the polling memo. "Despite his attempts to distance himself from Washington Democrats, Pryor's party and its leaders continue put him at a disadvantage and will likely do so throughout the race."

The live-caller poll of 600 likely voters was conducted from May 6-8 and has a margin of error of plus or minus 4 percent.