Critics of the UN treaty banning the bomb argue that nuclear weapons have helped to prevent World War III and are essential for international security. A world without nuclear weapons, they say, would be a world of greater war and military aggression. As I explain below, however, the reduction and elimination of nuclear weapons envisioned in a nuclear ban would help to make the world more secure not less.
The contention that nuclear weapons have kept the peace between the great powers since World War II is simplistic and unprovable. Russia and the United States are certainly more wary of confronting each other because of nuclear weapons, but this is not the only consideration preventing a conflagration. Europe was once the cauldron of world war, but over the decades it has become a politically and economically integrated community of states at peace with one another, notwithstanding Brexit and other tensions. France and Germany still have many differences but the prospect of war between them has become inconceivable. The United States and China are geopolitical rivals but they are so deeply intertwined financially and economically that war would bring incalculable damage to both. The absence of war is the result of many complex developments and cannot be ascribed to a single factor.
Arguments about the supposed necessity of nuclear weapons are conflated with the theory of deterrence—that countervailing power and the capacity to retaliate are necessary to prevent aggression. The advent of nuclear weapons has changed the calculus of security among nations, especially the great powers, but conventional military capabilities are also an important form of deterrence. Advances in the lethality and precision of weapons technology have greatly increased the potency of non-nuclear deterrence. In the case of North Korea, the weight of vastly superior U.S. and South Korea conventional forces is a more credible deterrent than the threat of nuclear retaliation.
Deterrence is usually understood in terms of destructive power: stand down and cooperate or I will punish you. But the prevention of war can also be framed in the context of constructive and integrative power: cooperate and you will receive benefits and both of us will gain. This is the basis for diplomacy, the crafting of agreements that provide mutual benefits to increase the value of cooperation over confrontation. This was the approach employed successfully in the Iran nuclear deal, and that worked during the time of the Agreed Framework with North Korea in the 1990s.
The security argument for nuclear deterrence can be turned around. The existence of nuclear weapons exerts what Jonathan Schell termed a “proliferance effect,” giving other countries the motivation or excuse to pursue their own nuclear options, thereby increasing insecurity and the risk of war. Recall that the US invasion of Iraq was justified as a war to “disarm the dictator”; that voices in the US and Israel advocated military strikes to counter Iran’s nuclear capability; and that the current occupant of the White House has threatened “fire and fury” against Pyongyang.
The opponents of nuclear abolition claim that disarmament would place the US and its allies at a disadvantage against Russian and other potential adversaries, but any realistic process of arms reduction would require mutual agreement and negotiation. This was the case with the Reagan-Bush-Gorbachev arms reductions that marked the end of the Cold War and which significantly enhanced international security. The process of negotiating disarmament was both a product of and contributor to lessened political tensions between East and West and became a stepping stone toward greater security not only in Europe but internationally through greater US-Russian cooperation at the UN Security Council. Although relations between Washington and Moscow have soured badly since then, disarmament diplomacy enhanced international cooperation in the past and could do so in the future.
The treaty banning the bomb will not result in the immediate elimination of nuclear weapons, but it will strengthen the legal and political basis for moving in that direction. The road toward nuclear zero will be long and difficult, requiring gradual, balanced reductions and confidence building measures among the participating states. That future may be hard to imagine today amidst global tensions with North Korea and Russia, but the argument for denuclearization remains valid and is more urgent precisely because of the current danger. The UN treaty reaches toward that future and deserves American political support.
 Kenneth Boulding, Three Faces of Power, (Newbury Park, California: Sage Publications, 1989).
 Jonathan Schell, “The Folly of Arms Control,” Foreign Affairs, vol. 79, no. 5, September/October 2000.
David Cortright is the Director of Policy Studies and Director of the Peace Accords Matrix at the Kroc Institute for International Peace Studies