If Iran has the expertise and infrastructure to build nuclear weapons—even if it chooses not to do so—and at the same time it comes in from the cold, joining the community of nations (and the World Trade Organization) on equal terms with the ability to exploit fully its huge oil and gas reserves, then it becomes not only a regional player, but a regional superpower.

That door is now opening. And does that make the world safer? There are certainly many reasons for Americans, Europeans and others to distrust a country that has played ruthlessly—and often with great success—on the shadowy battlefields of terror and counter-terror. Iran created and sustains Hezbollah. It is, along with Russia, the key ally of the savage Assad regime in Syria.

But the Obama administration has conceded a crucial point that the neocons of the George W. Bush administration and the hawks in Israel never wanted to admit: Iran’s leaders are not insane, and least of all Supreme Leader Ali Khamenei and the current president, Hassan Rouhani, elected last summer…

The number one priority of the mullahs throughout their reign has been the preservation of their theocratic rule, and the Obama administration decided to deal with them on that basis. The White House has reassured them privately and publicly that “regime change” is not its goal, although that might be the result if the nuclear issue led to war. The mullahs have no reason to want that. And neither does Washington.