Truthfully, I do not know if we can get the elements of a deal just described.

While critics—and op-ed writers in the comfort of their offices—can easily say what an agreement should contain, our negotiators have to find a way to deliver across the room from Iranian negotiators who are under as much pressure as they are—with their own domestic politics, redlines and hard-liners back home. What I do believe is that if we can get these remaining elements, the agreement will be in the national security interests of the United States. Critics of the Lausanne framework would consider even the agreement described here a “bad deal” and will call on Congress to reject it or the next president to repeal it. But while true that it could always be better—which is true, of course, for every diplomatic agreement ever reached—letting the perfect be the enemy of the good would be a historic mistake.

A deal that verifiably constrains Iran’s enrichment program until at least 2025 or 2030, limits its R&D, prevents the production of weapons-grade plutonium and reprocessing and provides unprecedented transparency and verification forever, would be an enormous win for the United States and its partners. Kill that deal, and tomorrow Iran can resume enrichment including to higher levels, keep its fissile material stockpile, finish building its heavy water reactor, and do unlimited R&D, all without transparency or international supervision.