There is also a connection with interventions aimed at regime change. No state exposed to another’s nuclear weapons is likely to invade it, much less use force to bring down its government. North Korea’s regime has pretty much made itself immune from this sort of intervention, to say nothing of more consequential nuclear powers such as China and Russia. Ditto Pakistan, even it were to unravel some day. And it’s hard to imagine the sort of campaign that toppled Muammar Qaddafi’s regime had Libya possessed nuclear weapons.

This dynamic would suggest that a state that renounces nuclear weapons should be given a pledge by the major powers that it will not be the target of a war for regime change. But there are practical problems here. Would it be feasible to provide an unconditional pledge, one that would hold regardless of what states did to their citizens or to other states? Would states offered this pledge trust it enough to forsake nuclear weapons? Yet without tackling this problem, it’s likely that a number of states will continue to consider nuclear weapons a deterrent against regime change.

This Crisis Will Happen Again

It is possible to imagine a solution to the current impasse between Iran and the P5+1, but not if the calculation remains that Iran will abandon the quest for an independent nuclear fuel cycle to ease the pressure created by sanctions. There must be compromises by both sides if war—with all of its uncertainties and hazards—is not to be the only option left. An agreement with Iran should be the focus for the moment, but a lasting solution to nuclear proliferation would require existing nuclear-weapons states to ante up.

Iran is but a particular manifestation of a larger problem. We will see this movie again.

Rajan Menon is the Anne and Bernard Spitzer Professor of Political Science at the City College of New York/City University of New York, nonresident senior fellow at the Atlantic Council and the author, most recently, of The End of Alliances.