How do you think a nuclear weapon in the hands of a theocracy whose leaders regularly chant “Death to America” is going to go. They already have 60% Uranium purity and it doesn’t need the complex trigger mechanism that Plutonium requires. It’s not the desired purity level but it can be detonated.
The time to topple Iran from within is now. There will never be another chance like this in the foreseeable future.