Former Republican presidential candidate Ron Paul on Saturday dismissed as a “joke” the demand by U.S. senators of his party that they must approve a potential agreement over the Middle East country’s nuclear capabilities.

“I strongly disagree with the motivation of that statement made by so many members of Congress, especially in the Senate,” Paul said at a conference on liberty at the University of Texas at Austin, presumably referring to an open letter senators sent to Iranian officials describing any deal not approved by them as informal.

Paul, a longtime Lake Jackson congressman who left office in 2013, said Congress should have a role in reviewing agreements, but he questioned whether the senators really cared about the constitutional questions or just wanted to undermine the deal.

“They’re out to stop peace,” he said. “They’re terrified that peace might break out.”