As tensions escalate, the window to avoid spiraling conflict in the Middle East and beyond is narrowing. Concerns that Iran might develop nuclear weapons are unlikely to be resolved by war. Any durable solution must come from treaties, diplomacy and enhanced verification—not force. The legal framework already exists but needs strengthening.The Treaty on the Non-Proliferation of Nuclear Weapons (NPT) governs the global nuclear order. The next NPT Review Conference convenes at the United Nations in New York later this month, and it’s pivotal.The NPT rests on a grand bargain: countries without nuclear weapons agree not to develop them in exchange for the five nuclear...