We are this evening bombarded with news stories variously announcing, celebrating, questioning, condemning the "breakthrough" at Lausanne.
In reality this means next to nothing. According to the assessments of the top US and Israeli spy agencies, the Iranians gave up a serious nukes program years ago.
Which is why we had to invent the concept of "break-out time." Not only do we have to prevent an actual nuclear weapon, we have to prevent them from thinking about an actual nuclear weapon.
As long as Israel has nuclear weapons, you can't blame Iran for thinking about them. After all, it is well proven that nuclear weapons have a salutary deterrent effect.
That's why Israel has them.
That's why Iran wants them.