“Negotiations with Iran, especially, will not be easy under any circumstances, but I suspect that they might be somewhat less difficult if the nuclear-weapon states could show that their requests are part of a broader effort to lead the world, including themselves, toward nuclear disarmament. Preventing further proliferation is essential, but it is not a recipe for success to preach to the rest of the world to stay away from the very weapons that nuclear states claim are indispensable to their own security.”