The signatories to the deal include Russia, China, France, UK, the EU, Iran, and the US. Why should the exit of the US end the deal? We left TPP and the Paris Climate Accord and they survived.
It is up to Iran to decide if it still honors the agreement. If Iran leaves, then it demonstrates that Iran was always bent on getting nuclear weapons. There could very well be an ongoing clandestine program despite the verification inspections. Iran lied at the very onset of the deal.
It is ironic that Russia is part of this deal. The Dems are calling for more sanctions on Russia as part of their campaign to take down Trump for collusion with the Russians. No one seems to be questioning Russia’s motives for signing the Iran deal or the part Russia played in the negotiations. Russia built the Iranian nuclear plant and has a deal to build three more.
The truth is that everyone benefited from the Iran deal except the US.
Nobody’s foolin’ nobody. If the sun rises in the East, then it demonstrates that Iran was always bent on getting nuclear weapons.