A Fascinating Test of the UN Charter?

The Western European "signatories" to the Iran nuclear deal are starting the dispute resolution mechanism of the 2015 Iran nuclear deal. They say it is to save the deal rather than trigger so-called "snap-back" UN sanctions. I don't think snap-back provisions are legal and I don't think Russia and China would have agreed to the deal if they thought those provisions could be enforced.

They have to destroy the deal in order to save it:

Triggering the mechanism is regarded in European capitals as a means to preserve the JCPOA, and not the start of a process leading to an imminent reference to the UN Security Council and a “snap-back” to pre-2015 sanctions.

I don't think there is any chance in the world that UN sanctions can snap back under any circumstances:

And let me add a question I've asked before. Can the United Nations charter be amended by this deal to carve out an exception to the veto power of the 5 permanent members of the Security Council?

Here's what the Chapter V, Article 27 of the UN charter says about the veto:

1. Each member of the Security Council shall have one vote.
2. Decisions of the Security Council on procedural matters shall be made by an affirmative vote of nine members.
3. Decisions of the Security Council on all other matters shall be made by an affirmative vote of nine members including the concurring votes of the permanent members; provided that, in decisions under Chapter VI, and under paragraph 3 of Article 52, a party to a dispute shall abstain from voting.

Because I can see the Russians or Chinese objecting to the whole notion that UNSC resolutions can be reimposed after 30 days of inaction by the Security Council. What do we do when the Russians and Chinese (probably correctly, but it has been a long time since I had an international law class) argue that this deal provision is invalid and that no sanctions resolutions can go into effect without 9 votes, including the concurrence of the five permanent members, and they will not go along with it?

Russia and China would never weaken their UN Security Council veto power. Certainly Obama would never even think about triggering that provision, nor would Clinton had she won. So Russia and China probably thought there was no harm in agreeing. And then the deal would have expired and Iran would be off to the nuclear races.

But here we are. And Europeans are starting a process that could kill the deal in the hopes of saving it.

It would be fascinating to see the dispute process get to the point of those snap-back provisions coming up. There is no way Russia or China will allow those to go through, given the shaky legality of the deal.