Nuclear Security and Nonproliferation: What Each Position Is Protecting

In January 2023, the Bulletin of the Atomic Scientists moved the Doomsday Clock to ninety seconds to midnight — the closest it had ever been set in its seventy-six-year history. The announcement cited the war in Ukraine, the collapse of the last major arms control treaty between the United States and Russia, and what the scientists called "the return of the nuclear specter" to international politics. For most people, the Doomsday Clock is a curiosity they note and then set aside. For the small community of people who spend their professional lives studying nuclear weapons policy, the movement was not metaphorical.

The nuclear weapons debate is unusual among major policy disputes in one important way: all four of its main positions are held by serious, well-informed people who have spent decades thinking about the problem. The person who believes nuclear deterrence has preserved the peace, the person who believes deterrence is a morally incoherent doctrine built on the threat to commit mass murder, the person who believes neither position is reachable and the only path forward is careful arms control, and the person who believes the nonproliferation regime is an inequitable power arrangement enforced by the strong against the weak — none of these people is simply wrong, or uninformed, or operating on bad faith. They are each protecting something real.

What deterrence advocates are protecting

The deterrence position rests on a disturbing empirical claim: the most destructive weapons ever built appear to have prevented the most destructive kind of war. Since 1945, there has been no direct military conflict between the major powers. The "long peace" — a phrase associated with historian John Lewis Gaddis — is anomalous by the standards of modern history. Great-power wars had been routine before the atomic age. They have been absent since it began. The simplest explanation, not accepted by everyone but taken seriously by most realist scholars of international security, is nuclear deterrence.

Deterrence advocates are protecting the peace that currently exists. Not the peace of an ideal world, but the specific, imperfect absence of great-power war that has persisted for eight decades. Their argument is not that nuclear weapons are good, or that the current situation is just, but that unilaterally dismantling the architecture that seems to have produced this outcome — without any comparable replacement — is a gamble with stakes too high to risk. Bernard Brodie, the first theorist to seriously reckon with the atomic bomb, wrote in 1946 that the bomb had fundamentally altered the purpose of military strategy: its chief purpose was now to avert wars, not to win them.

They are protecting the credibility of extended deterrence — the security guarantees the United States provides to Japan, South Korea, Germany, and dozens of other countries that have agreed not to develop nuclear weapons in exchange for the assurance that they are covered by the American nuclear umbrella. If that umbrella is perceived as unreliable, the incentives for additional proliferation increase dramatically. The deterrence case for maintaining robust nuclear forces is partly about the weapons themselves and partly about what their existence signals to states that are watching to decide whether they need their own.

They are protecting sobriety about human nature and power politics. The realist tradition in international relations holds that states compete for security in an environment where no authority enforces agreements, and that this fundamental condition has not changed because of the existence of international institutions. A world in which major nuclear-armed states have verifiably eliminated their weapons would require a degree of mutual trust and verification that does not currently exist and cannot be wished into existence. Deterrence advocates are not indifferent to the risks of nuclear weapons; they believe they are more sober about those risks than their critics.

What humanitarian abolitionists are protecting

The abolitionist position begins with a different framing question: not "does deterrence work?" but "what are we actually threatening?" Any coherent deterrence doctrine rests on the credible threat to use nuclear weapons if deterrence fails. Using nuclear weapons against a city means killing hundreds of thousands of civilians and, depending on yield and targeting, potentially triggering a nuclear winter that would damage global agriculture for years. Abolitionists argue that this threat is not a regrettable backstop of a peaceful policy. It is the policy. The peace, on this view, is built on the implicit promise to commit mass atrocity if called upon.

Abolitionists are protecting the principle that some weapons are categorically off-limits under international humanitarian law — the principle of distinction (combatants versus civilians), proportionality, and the prohibition on weapons that cause unnecessary suffering. Nuclear weapons cannot, by their nature, satisfy these requirements. The International Court of Justice's 1996 advisory opinion found that the threat or use of nuclear weapons would "generally be contrary to the rules of international law applicable in armed conflict" and specifically to the principles of humanitarian law. The 2021 Treaty on the Prohibition of Nuclear Weapons (TPNW) — which entered into force with fifty ratifications and reflects the position of the vast majority of the world's states — codifies this view: nuclear weapons are not a special category of strategic asset but a form of weapon that, like chemical and biological weapons, belongs in the category of the categorically prohibited.

They are protecting the argument that deterrence is not stable in the long run. The political scientist Ward Wilson has systematically challenged the empirical foundation of the deterrence argument in his book Five Myths About Nuclear Weapons (2013): the correlation between nuclear weapons and great-power peace is not as strong as claimed (conventional deterrence and the devastation of World War II may explain much of the "long peace"), and the probability of nuclear use, while small in any given year, is not zero. Over seventy-five years, the cumulative probability of at least one accidental or unauthorized use event, or a serious miscalculation, is substantial — and the consequences of any use event could be catastrophic and irreversible.

They are also protecting the communities that have borne the costs of nuclear programs without wielding their power. The populations of Hiroshima and Nagasaki. The inhabitants of the Marshall Islands and Nevada and Kazakhstan — communities subjected to atmospheric testing without meaningful consent. The workers in uranium mines, the downwinders, the people who have already paid the health costs of nuclear programs that were never theirs to authorize. The nuclear debate often proceeds as though the only costs at stake are hypothetical future harms. The abolitionists are also insisting on accounting for costs already incurred.

What arms control pragmatists are protecting

The arms control position occupies what is often called the pragmatic middle — though its advocates would resist the condescension in that framing. In 2007, a remarkable op-ed appeared in The Wall Street Journal under the names of George Shultz, William Perry, Henry Kissinger, and Sam Nunn — four former senior American officials who had spent decades at the heart of nuclear strategy and deterrence policy. They called for a world free of nuclear weapons. Not immediately. Not naively. But as a goal that required concrete, incremental steps toward arms reductions, treaty maintenance, and the creation of verification and trust-building regimes that would make eventual elimination conceivable.

Arms control pragmatists are protecting the institutions and agreements that reduce near-term risk. The Nuclear Non-Proliferation Treaty (NPT) is imperfect — it created a two-tier system in which states that had weapons when it was negotiated kept them, while all others forswore them — but it has been associated with a dramatic reduction in the number of states with nuclear weapons programs. In the 1960s, John F. Kennedy predicted there would be twenty-five nuclear-armed states by the 1970s. There are nine. Something held the number down, and the NPT framework, however flawed, was part of it. The New START treaty, which limited U.S. and Russian deployed strategic nuclear weapons, expired in 2026 without a successor — and arms control pragmatists regard this as a genuine and serious deterioration of the security environment.

They are protecting the nuclear taboo — the normative prohibition on nuclear use that Nina Tannenwald's scholarship identified as a distinct constraint on decision-making, operating alongside but separately from rational deterrence calculations. Political leaders have, on multiple occasions when nuclear use might have appeared militarily advantageous, declined to use nuclear weapons. Tannenwald's argument is that this reflects not just cost-benefit analysis but a genuine norm: nuclear weapons are in a special moral category, and crossing that line would carry illegitimacy costs that no strategic benefit could fully compensate. Preserving that taboo — and not taking actions that normalize nuclear weapons as "just another option" — is itself a form of nuclear security.

They are protecting attention to the risks that are actually most likely to materialize. In the arms control framework, the most dangerous near-term scenarios are not a bolt-from-the-blue attack by a major nuclear power but: terrorist acquisition of nuclear or radiological material, accidental or unauthorized launch by any nuclear state, regional nuclear war between India and Pakistan, or miscalculation during a crisis. Eric Schlosser's Command and Control (2013) documents the history of nuclear accidents and near-misses — the broken arrows, the false alarms, the moments when the world came closer than most people know to a nuclear detonation. The arms control argument is partly that reducing the number and alert status of weapons reduces the probability of these scenarios independently of the deterrence question.

What NPT skeptics and sovereignty advocates are protecting

The fourth position is the least represented in mainstream Western policy debate, but it is held seriously in the Global South, in certain realist academic circles, and among scholars who look at the nonproliferation regime from outside the perspective of the states it most benefits. Its core claim is that the NPT is not a disarmament treaty — it is a freezing mechanism that enshrined the nuclear privilege of the five states that had weapons in 1968 while extracting a permanent prohibition from everyone else, backed by a "good faith" commitment to eventual disarmament that the nuclear states have honored mostly in the breach.

NPT skeptics are protecting the principle of sovereign equality in international law. The argument is that the nonproliferation regime functions as a kind of nuclear imperialism: powerful states reserve the right to possess weapons that they deny to others, and use that superiority to enforce compliance with arrangements that serve their interests. The states that have forgone nuclear weapons under the NPT have, in effect, trusted security guarantees from the major powers — guarantees that are conditional and not always reliable. Libya gave up its nascent nuclear program and was later subjected to military intervention. Ukraine surrendered the nuclear weapons on its territory after the Soviet collapse in exchange for security assurances in the Budapest Memorandum — and was invaded. North Korea watched these cases and drew the obvious lesson: the guarantees are not guarantees.

In realist academic circles, the scholar Kenneth Waltz made the most controversial version of this argument: that nuclear proliferation might, in some cases, stabilize regional conflicts by creating mutual deterrence between states that would otherwise be tempted toward conventional war. This is a minority position even among realists, but it follows logically from the deterrence argument applied consistently: if nuclear weapons prevent great-power war, why don't they also stabilize regional rivalries? The answer generally given — that regional powers are less stable, their command-and-control systems less reliable, their leaders more risk-acceptant — is not obviously wrong, but it does imply that the deterrence argument applies differently to different states based on implicit assumptions about governance and reliability that can shade into double standards.

They are also protecting honest accounting of the NPT's core bargain. The treaty contains, in Article VI, a commitment by the nuclear states to pursue negotiations in good faith toward nuclear disarmament. By most assessments, this commitment has not been seriously honored. The United States and Russia have reduced their arsenals significantly from Cold War peaks, but both are currently modernizing their forces and neither is pursuing negotiations toward elimination. The NPT skeptics' most defensible point is that the regime asks a great deal of non-nuclear states — accepting their own vulnerability and forgoing autonomous security options — in exchange for a disarmament commitment that has not materially advanced.

Where the real disagreement lives

The surface debate in nuclear policy is often about capabilities and numbers: how many warheads, what delivery systems, which treaties. Underneath the surface debate are three deeper disputes that rarely get named directly.

Is deterrence a stable long-run equilibrium or a high-variance gamble? Deterrence advocates look at seventy-five years without great-power war and see evidence that the system works. Abolitionists and arms control advocates look at the same period and see a series of close calls — Stanislav Petrov's 1983 decision to disregard a false alarm that showed incoming missiles; the 1995 Norwegian weather rocket incident that reached Yeltsin's launch authorization briefcase — and conclude that we have been lucky as much as safe. These are arguments about base rates for rare events where the sample size is too small to adjudicate statistically. They will never be resolved by data alone.

Whose security is centered. The deterrence and arms control debates are largely conducted from the perspective of the states that possess nuclear weapons, and they focus on the stability of the relationships between those states. The humanitarian and NPT-skeptic positions insist on centering different constituencies: the populations of cities that would be destroyed in any nuclear exchange, the communities that have already borne the costs of nuclear programs, and the non-nuclear states whose security is shaped by arrangements they did not negotiate and cannot revise. The conversation looks different depending on where you stand in the international hierarchy.

Whether the status quo is the baseline or a problem. Deterrence advocates compare the present nuclear order to the hypothetical dangers of a world in which some states have disarmed and others have not — a world they find more dangerous. Abolitionists compare the present nuclear order to a world in which elimination has been achieved, and find the current arrangement both dangerous and morally indefensible. NPT skeptics compare the current regime to a hypothetical arrangement in which the non-proliferation burden is either shared symmetrically or enforced honestly. These are not arguments about the same counterfactual, which is why they so rarely make contact with each other.

What sensemaking surfaces

Holding this map whole, a few things become visible.

The deterrence case is empirically strong and morally uncomfortable. The same people who most forcefully make the argument that nuclear weapons have prevented great-power war are also implicitly acknowledging that what has prevented war is the credible threat to kill millions of civilians. These are not separable claims. The deterrence argument works precisely because the weapons are catastrophic — and the uncomfortable moral implication is that the peace is, in part, a product of the willingness to threaten mass atrocity. Deterrence advocates who engage this question seriously — and some do — acknowledge it as a genuine moral cost.

The abolitionist case is morally coherent and operationally thin. The argument that nuclear weapons violate humanitarian law, that the deterrence gamble cannot hold indefinitely, and that the costs have been borne inequitably is compelling. What the abolitionist position struggles to provide is a path: a credible account of how you get from the world as it is — where deterrence is interlocked into the security calculus of nine states — to a world where elimination is verifiable and stable. The TPNW has near-universal support among non-nuclear states and zero ratifications from nuclear ones. The gap between normative aspiration and strategic reality has not been closed.

The arms control position may be the most practically important precisely because it is the most modest. The collapse of the bilateral arms control architecture between the United States and Russia — the end of the INF Treaty, the expiration of New START — is a genuine and underreported deterioration of the security environment. Neither of the bold positions (deterrence forever, or abolition now) has much to say about the specific and real danger of entering a new era without the transparency and limitation measures that arms control provided. The most urgent practical question may not be "should nuclear weapons exist?" but "how do we prevent the gradual erosion of all the arrangements that reduced the likelihood of their use?"

And the NPT-skeptic argument, at its best, offers a corrective to all three other positions: the nuclear debate in the West is primarily a debate among the powerful, conducted in terms that serve the powerful, about a system that the powerful designed. Taking non-nuclear states seriously — their security, their legitimate grievances about the NPT's broken promise, their exposure to risks they did not create — does not resolve the strategic questions. But it changes what kind of answer would count as just.