Sen. Tom Cotton, R-Ark., on Tuesday said that President Trump must first decertify the Iran deal before Congress makes any changes to the legislation governing the agreement.

Trump is facing an Oct. 15 deadline to certify to Congress that Iran is in compliance and that the deal, known formally as the Joint Comprehensive Plan of Action, is still in the vital national security interest of the United States. Under a 2015 act of Congress, the president must recertify the deal every 90 days. Though Trump has indicated that he doesn't want to certify it, advisers have persuaded him to do so on two prior occasions and are now working aggressively to get him to do so again.

The State Department, according to the Associated Press, has been pushing one option that would have Trump certify the deal and then work to make changes. One of the possible changes that has been circulating in Washington over the past week would involve amending the Iran Nuclear Agreement Review Act that governs the deal by altering the certification process. The idea would be to change it in a way so that Trump doesn't have to be put in the embarrassing position of recertifying a deal every three months that he has been mocking for years.

But when asked about this prospect by the Washington Examiner, Cotton rejected the notion that Congress would make changes before Trump decertified.

"If the president doesn't take the step first of declining to certify that the JCPOA is in our vital national security interest under the Nuclear Agreement Review Act, everything else in my opinion is hot air," Cotton told the Washington Examiner during a meeting in his senate office. "The Democrats won't believe us, unfortunately, not many people in the State Department will believe him, European partners won't believe him, and maybe most importantly, the ayatollahs won't believe him."

He continued, "The critical first step is declining to certify under the Nuclear Agreement Review Act that the JCPOA is not in our vital national security interest. I don't see how anybody can argue that it is. At that point, we can consider amendments to the Nuclear Agreement Review Act — things like addressing the sunset positions in the JCPOA, and the advanced nature of the centrifuges that Iran is allowed, their ballistic missile systems, and so forth. But it takes a refusal to certify the JCPOA to focus the minds of Congress, the State Department, of our European partners, and of Iran."

He emphasized that declining to certify citing vital national security interests, is "not quibbling about Iranian technical compliance or non-compliance. I don't see how anybody who looks at the facts ... can say that that deal is in our vital national security interests."

Trump blasted the deal in a speech to the United Nations on Tuesday. "The Iran deal was one of the worst and most one-sided transactions the United States has ever entered into," he said. "Frankly, that deal is an embarrassment to the United States, and I don't think you've heard the last of it, believe me."