Recall that this was a treaty that should never have been adopted without two-thirds approval in the Senate, as required by the Constitution. That didn’t happen — because a compliant Republican Congress passed the Iran Nuclear Agreement Review Act, which provided that the president certify to Congress every 90 days that the suspension of sanctions against the regime is “appropriate and proportionate” with respect to its illicit nuclear program.
And that’s what Trump didn’t do. He didn’t tear up the treaty, or even decertify anything. Rather, he failed to certify, and simply told the truth. Iran isn’t permitting the nuclear inspections the treaty contemplates, and the Revolutionary Guard, which controls much of the government, is a terrorist organization.