The nuclear ban treaty and competing nuclear norms

Editor’s note: This article is part of a collection to mark the occasion of the entry into force of the Treaty on the Prohibition of Nuclear Weapons.

When the 50th country ratified the Treaty on the Prohibition of Nuclear Weapons (TPNW) last week, setting up the treaty to enter into force in January 2021, the US government reiterated a longstanding talking point about it. State Department spokeswoman Morgan Ortagus asserted: “The TPNW will not result in the elimination of a single nuclear weapon.”

By saying this, the US government is making the argument that no current nuclear weapon possessor state—itself included—intends to join the treaty. Nor have states protected by extended nuclear deterrence so far indicated any plans to join it. The talking point seems to suggest the treaty is pointless—it will not do the one thing it set out to accomplish, ridding the world of nuclear weapons.

But the very fact of the strong vocal opposition is telling. If the treaty is worthless, why have the nuclear weapon states felt the need to so vehemently denounce it? Why did the United States, in a last ditch effort to prevent its entry into force, try to persuade current members to withdraw from it? Nuclear weapons states could, after all, simply ignore the new treaty and not provide it with any undue additional attention.

The reason is because they fear the treaty, even if they do not plan to join it. Why? The nuclear weapon states are aware of the long-term potential effect of the norm that underpins it: the idea that it is not appropriate for any states to possess nuclear weapons. In attempting to stigmatize nuclear weapons among populations around the world, the treaty risks bringing attention to the devastation wrought by nuclear weapons to members of the general public. Though nuclear weapon states do not plan to join the treaty today, they are concerned that in the short- to medium-term their allies will face pressure to join the treaty, undermining extended nuclear deterrence. In the longer term, the norm enshrined in the treaty could influence their own publics, potentially turning citizens against nuclear weapons. A public against nuclear weapons will not support nuclear deterrence or the immense expense involved in maintaining and updating nuclear arsenals. For a government that believes that nuclear deterrence is a source of strategic stability and existential security, this norm is dangerous.

The United States in particular knows the power of strong, universal norms, especially in the nuclear realm. For 50 years, the US government has been the most important force in promoting the universalization of the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) in order to promote a global norm against the spread of nuclear weapons. A 1992 cable from the US State Department to several US embassies reads: “The NPT has proved its value over the years: It has established an international norm under which virtually all nations view the further spread of nuclear weapons a grave threat to regional and global security.” Recognizing the value of a strong nonproliferation norm, the US government promoted the NPT to all states, even those that had little interest in nuclear technology. As the US Government Accountability Office explained in a 1980 report on US efforts to promote the NPT: “But countries with little or no nuclear material are not ignored, as adherence by just one additional state increases by two the difference between the number of parties and nonparties and thereby serves to further isolate the nonparty states.”

Universal norms have power—US leaders know this. For proponents of nuclear deterrence like the US government, the norms of the NPT are strategically valuable because they allow the United States and four other states to maintain their nuclear weapons while keeping the rest of the world from possessing their own. In contrast, the norm promoted by the ban treaty is meant to apply to all states and so US leaders fear its long-term effects.