The chairman of the Senate Foreign Relations Committee is predicting that President Trump will not extend the United States’ participation in the Iran nuclear pact past May — a development likely to please the deal’s critics but throw into turmoil the international effort to keep Tehran’s nuclear ambitions in check.

Sen. Bob Corker (R-Tenn.), the lawmaker most directly in touch with the Trump administration on matters concerning Iran, told CBS on Sunday that “right now, [the Iran deal] doesn’t feel like it’s going to be extended.”

“I think the president likely will move away from it,” he said, unless the White House and European leaders agree on a way to supplement the deal with harsher punitive actions if Iran ever seeks to develop a nuclear weapon.

Corker added that he did not think that pulling out of the deal would complicate the planned, “somewhat unorthodox” talks with North Korea, also expected to take place by the end of May.

Corker and Trump have had a mixed relationship, with the two coming to verbal blows in October. That was just a week before Trump decided not to certify that Iran was in compliance with the terms of the nuclear pact, despite assurances from the International Atomic Energy Agency and advisers such as Defense Secretary Jim Mattis that Tehran was holding up its end of the bargain.

Over the past several months, Corker has worked closely with national security adviser H.R. McMaster, Secretary of State Rex Tillerson and others to keep the president from fulfilling his campaign promise to rip up the Iran deal. But with Tillerson on his way out of the administration and McMaster possibly next on the chopping block, there are few left in the president’s circle of trusted national security advisers who defend upholding the deal.

The recent nomination of CIA Director Mike Pompeo as Tillerson’s replacement further suggests that hard-line critics of the pact are about to hold more sway in the administration.

The multilateral Iran deal works as a trade-off: In exchange for Iran keeping its nuclear ambitions in check, including submitting to regular international inspections of its facilities, the other countries and parties in the pact agreed to ease up on nuclear-related sanctions against Tehran. For the United States, upholding the bargain depends on the president, who must periodically agree to waive the nuclear sanctions against Iran that remain part of U.S. law. The next waiver deadline is May 12.

Trump has been reluctant in the past to extend the waivers, and in January warned that Congress must “fix the deal’s disastrous flaws — or the United States will withdraw.” Corker has maintained, however, that Congress cannot “fix” the deal until the White House secures the buy-in of European nations, to keep the agreement intact.

Corker speculated that under pressure, the White House and European leaders may be able to strike a last-minute accord.

“As we get within two weeks of the May 12th date, that could change,” he said of his prediction that Trump would back away from the agreement.

But when asked to predict whether he thinks Trump would pull out of the Iran deal on that date, Corker said simply: “I do. I do.”

Corker would not say whether Pompeo would be installed as the new secretary of state by May. Confirmation hearings for Pompeo are expected to begin in April, but Corker warned that because it is an election year, things are “more partisan” and nominations could move through the Senate slowly.

Sen. Rand Paul (R-Ky.), a member of the Foreign Relations Committee, has pledged to oppose Pompeo’s nomination, meaning that a Democrat on the 21-member panel will have to support Pompeo for the committee to recommend that the full Senate confirm him.