John Kerry actually said...

They have an ability to go enrich again. What is the next step for the United States?

What this agreement is supposed to do is stop them from having a nuclear weapon.

If the P5+1 agreement is rejected by the United States, I don't think we can rely on those other countries keeping that money locked up.

It is a lot easier to push back against an Iran that doesn't have a nuclear weapon rather than one that does.