The letter was initially sent to House and Senate leaders from both parties on Tuesday with 190 signatures — among them several individuals who’ve held high-level positions in past administrations, including former Navy Vice Admiral John Poindexter, who served as President Ronald Reagan’s national security adviser. Retired Air Force Lieutenant General Thomas McInerney, who held various defense advisory positions during President Bill Clinton’s administration, is also a signatory.

The letter outlines a litany of complaints about the nuclear deal that Congress is slated to vote on whether to support or reject next month. “The agreement as constructed does not ‘cut off every pathway’ for Iran to acquire nuclear weapons,” the letter states. “To the contrary, it actually provides Iran with a legitimate path to doing that simply by abiding by the deal.”

The former military officials also assert that the deal is “unverifiable,” lamenting that the agreement allowed for a “secret side deal” between Iran and International Atomic Energy Agency that will ultimately prevent UN weapons inspectors “from reliably detecting Iranian cheating.”