Pryor, a two-term Democrat whose seat is considered one of the more vulnerable for Republicans to pick up in November, accused his opponent of running for his House seat simply as a means to run for Senate.
"When I look at Congressman Cotton's record, I don't see where he's passed a bill, I don't see where he's really accomplished anything in the House," Pryor told NBC's Kasie Hunt last month.
But Pryor may have stepped in it when Hunt asked about Cotton's service in the Army, where he served tours in both Afghanistan and Iraq.
"I appreciate that, I have great respect for that, I would never criticize anyone for serving our country, and I say thank you for that," Pryor said, but added that military service, in his mind, does not automatically qualify someone to become a senator.
"There's a lot of people in the Senate that didn't serve in the military," Pryor said. Then, he went on to say Cotton, also a graduate of Harvard Law, seems to behave as if he felt Arkansas voters owed him the Senate seat for his military service.
"And I think that's part of this sense of entitlement, that he gives off, that almost is like, I served my country, therefore let me into the Senate," Pryor said. "That's not the way it works in Arkansas."
Cotton jumped on Pryor's remarks, releasing a campaign ad Monday that highlighted why he believes his service prepared him for the Senate.
“Sen. Pryor says my military service gives me quote, ‘a sense of entitlement,’ so I brought in an expert,” Cotton said as Sgt. George Norton steps into the frame.
“Drill Sgt. Norton taught me how to be a soldier: Accountability, humility and putting the unit before yourself," Cotton continues. "That training stuck.”
Pryor was unopposed for his reelection bid in 2008, but finds himself running neck-and-neck with Cotton, a rising star, in the relatively sparse polling of the 2014 race so far. Cotton also represents southern Arkansas, an area where Pryor must rely on Democrats over performing if he hopes to hold onto his seat.