[Ed. – This Fox News piece articulates the U.S. view that as a Perm-5 UN Security Council party to 2231, we have the right to invoke snapback under the UNSCR. The view advanced by the others in the Perm-5 is that only JCPOA participants still in good standing can invoke the snapback. It’s a standoff. If the UNSC accepts the U.S. move as actionable, it has 30 days to come up with a plan the U.S. won’t veto. The other Perm-5 could also decide to let the U.S. snapback happen, but not comply with its terms. Either way, however, Trump has signaled that the U.S. will clamp down on Iran sanctions — which will affect anyone dealing in arms with Iran — after 18 October 2020, the effective snapback date.]
While Russia, China and other members of the JCPoA are clamoring to look for ways to halt snapback, it would seem they are fighting a losing battle.
UNSCR 2231 endorsed the JCPoA but never mandated members to implement it. It does, however, mandate restrictions on Iran for a limited period of time and mandates the snapback to prevent those restrictions from expiring if Iran misbehaves. …
You need to modify Security Council resolutions to modify international restrictions. And so the Security Council obliged the request to help the parties get a deal, but it built in the snapback as an institutional guarantee – because no sideshow political agreement can ever supersede the authority of the Council.
The JCPoA binds the few states that are part of the political agreement while a UNSCR binds all members of the U.N.
The U.S. may have lost its rights to use the mechanisms of the JCPoA political agreement but … permanent member rights granted by a binding Security Council resolution … [supersede] the JCPoA’s authority.
Snapback will restore prior Security Council resolutions on Iran so that all the long-term restrictions, like the arms embargo, remain in place indefinitely.