Nearly all Senate Republicans sent a letter to President Donald Trump on Wednesday urging him only to agree to a nuclear deal with Iran that requires the full dismantlement of Tehran’s nuclear program. Eighty percent of House Republicans — 177 lawmakers — signed onto a nearly identical letter.

The Senate letter, led by Sens. Pete Ricketts (R-NE) and Ted Cruz (R-TX) and co-signed by every Republican senator except Sen. Rand Paul (R-KY), calls on the Trump administration to follow through on its “explicit warnings” that Tehran “must permanently give up any capacity for enrichment.” The House version of the letter was led by Rep. August Pfluger (R-TX), the chairman of the Republican Study Committee, the largest conservative caucus in the House.

The letters, drafts of which were first reported by Jewish Insider last week, serve as a clear message to the president from congressional Republicans of their expectations that a new nuclear deal with Iran must cut off its nuclear enrichment capabilities permanently, amid inconsistent public messaging from the administration on the subject. The letters frame the appeal as a message of support for Trump’s position on the issue.

“You and your administration have therefore correctly drawn a redline against any deal that allows Iran to retain any enrichment capability,” the Senate letter reads, pointing to the language used in Trump’s National Security Presidential Memorandum on Iran and comments from him and Steve Witkoff, his Middle East envoy, about the need for full dismantlement.

“We cannot afford another agreement that enables Iran to play for time, as the JCPOA did. The Iranian regime should know that the administration has Congressional backing to ensure their ability to enrich uranium is permanently eliminated,” it continues.

The letters make the case that verification protocols to allow limited Iranian nuclear enrichment, as were used under the 2015 Joint Comprehensive Plan of Action and have been floated by some administration officials, are no longer a viable solution, given the advancement and expansion of Iran’s nuclear program since then.

“The scope and breadth of Iran’s nuclear buildout have made it impossible to verify any new deal that allows Iran to continue enriching uranium,” the Senate letter states, citing the International Atomic Energy Agency’s latest report on Iran’s nuclear activities. 

The letters criticize the JCPOA, which they call “deeply broken,” and praise Trump’s decision during his first term to withdraw from that deal and noting that he said at the time that it “allowed Iran to continue enriching uranium and, over time, reach the brink of a nuclear breakout.”

“The JCPOA allowed Iran to sell oil, provided waivers allowing third countries to help Iran build out its nuclear program, and included the termination of United Nations sanctions on the regime,” the Senate letter reads. “Despite critics claiming your withdrawal from the deal would allow Iran to advance its nuclear ambitions, the Iranian regime remained deterred from making substantial nuclear progress throughout your term because of your maximum pressure campaign.”

It goes on to detail the Biden administration’s alleged undoing of that pressure, “functionally re-implementing the nuclear deal,” as they described it. 

“As you predicted, those policies indeed allowed Iran to reach the brink of nuclear breakout, which is where they are today,” the senators wrote. “The Biden administration made those concessions without any reciprocal concessions from Iran, and Iran even ceased providing international inspectors access to significant parts of its nuclear program in the early days of the Biden administration.”