ASSOCIATED PRESS/Steve Karnowski Minnesota Attorney General Keith Ellison discusses health care at a press conference on Tuesday. He is encouraging Congress to reject a deal to lower drug prices through arbitration.

Minnesota Attorney General Keith Ellison (D) blasted the idea of using arbitration to lower Medicare’s prescription drug prices as “sort of a sellout to Big Pharma,” challenging congressional progressives to vote down any deal with President Donald Trump that includes arbitration.

“To use arbitration to deal with drug pricing seems like a loser from the start. It’s sort of a sellout to Big Pharma,” Ellison told HuffPost. “Democratic leadership should know that, if they don’t actually know that.”

Ellison, who was a co-chair of the Congressional Progressive Caucus until 2017, called on the current CPC heads, Reps. Mark Pocan (D-Wis.) and Pramila Jayapal (D-Wash.), to block any drug price deal with arbitration in it.

“The progressive caucus should not take any crap from leadership here,” he said. “The progressive caucus is saving Democratic leadership from themselves.”

Wendell Primus, a top adviser to House Speaker Nancy Pelosi (D-Calif.), is in talks with the White House to draft a bill that Trump would be willing to sign aimed at lowering drug prices.

Primus is reportedly pursuing legislation that would allow Medicare and drug makers to enter into arbitration, in which a third-party intermediary could adopt one of the parties’ proposed prices or come up with a price on their own.

Consumer groups and progressive lawmakers have publicly criticized the prospect of such a deal, arguing instead for legislation that empowers the federal government to threaten companies’ drug patents if they do not provide lower prices.

These critics fear that Primus’ plan would only apply to a limited set of drugs and not even be binding for participating companies. But they also maintain that the arbitration process inherently privileges pharmaceutical companies by depriving the federal government of crucial leverage in negotiations.

Ellison, who has used his perch as Minnesota’s top law enforcement official to take on drug-makers, focused on the latter point.

“Arbitration is notoriously bad for people who are on the other side of the table from a larger, greater entity,” he said. “All it does is advantage the party with the superior bargaining position.”