All it really promises is that, assuming the Iranians don’t cheat, they will need a year to get from the decision to make a bomb to making a bomb — and in eight years’ time they’ll be permitted to buy the ballistic missiles to deliver a nuclear strike.
The “year to make a bomb” is not good news for Democrats who want to support their president but don’t want to permit a nuclear Iran. But that’s where the smart structure of the deal comes in.

It’s full of temporizing numbers — no conventional weapons purchases for five years, no ballistic missile purchases for eight years, supposedly no weapons-grade uranium for 10 to 15 years.

These numbers suggest any crisis will happen in a future in which many current members of Congress will no longer be serving.

This time-stretch will, I fear, be enough for many Democrats.