There are three sets of reasons for a palpable rise in nuclear anxieties around the world: growing nuclear arsenals and expanding roles for nuclear weapons, a crumbling arms-control architecture, and irresponsible statements from the leaders of some nuclear-armed states.

One way to counter this would be for the P5 (China, France, Russia, the UK and the US—the five permanent members of the UN Security Council, which are also the five states recognised by the Nuclear Non-proliferation Treaty as lawfully possessing nuclear weapons) to co-sponsor a resolution affirming that ‘a nuclear war cannot be won and must never be fought’.

Ronald Reagan first made ^[1] that statement in 1984, and he and Soviet leader Mikhail Gorbachev reaffirmed ^[2] it in 1987 at the signing of the historic Intermediate-Range Nuclear Forces Treaty. Today, their successors seem determined to restart a nuclear arms race and look for ‘usable’ nuclear weapons.

India, Pakistan and North Korea are enlarging their nuclear arsenals as fast as they can. China’s military has called for ^[3] a strengthening of its nuclear-deterrence and counter-strike capabilities. Earlier this month in Beijing, the People’s Liberation Army paraded a range of new missiles, including the DF-41 ^[4] heavy intercontinental ballistic missile and the DF-17 ^[5] hypersonic glide vehicle.

In 2017, Paul Selva, a general in the US Air Force who was then serving as vice chair of the Joint Chiefs of Staff, said the future of nuclear deterrence ^[6] lay in small, low-yield, usable nuclear weapons. The Department of Defense’s 2018 nuclear posture review ^[7] promised two new weapons: a low-yield warhead for the Trident submarine-launched ballistic missile, and a new nuclear-armed sea-launched cruise missile.

Russian President Vladimir Putin responded in March 2018 with boasts of a new array of invincible nuclear weapons ^[8] designed to evade or penetrate US anti-missile defences anywhere in the world. Earlier this year he issued a warning ^[9] that Russia could place hypersonic nuclear weapons on submarines deployed near US waters and is developing the ability to trigger a radioactive tsunami in densely populated coastal areas using a new, nuclear-powered underwater drone. Russia could also deploy nuclear-powered cruise missiles ^[10] with unlimited range by 2025, several failed tests to date notwithstanding.

The expanded arsenals reflect the disintegrating framework of nuclear-arms control. The US withdrew from the Anti-Ballistic Missile Treaty in 2002. President Donald Trump has exited the Iran nuclear deal, killed off the INF Treaty, and rebuffed Russian overtures to extend New START. The Comprehensive Test Ban Treaty ^[11] hasn’t yet entered into force. Negotiations on a fissile materials cut-off treaty are yet to commence.

On 22 August, invoking the moral authority of the first city attacked with an atomic bomb, an international group of high-level experts issued the ‘Hiroshima urgent appeal ^[12]’ to maintain existing arms-control pacts as critical pillars of strategic stability. On 12 September, 100 Euro-Atlantic senior leaders from 24 European countries issued a call ^[13] for a renewed commitment to arms control.

While the growing arsenals and collapsing pacts have attracted considerable media attention, the impact of the increased nuclear-tipped belligerent rhetoric is still largely below the radar. After the outbreak of the Ukraine crisis in 2014, facing hostile Western criticism of Russia’s backing of rebels in eastern Ukraine and its annexation of Crimea, Putin pointedly remarked: ‘Russia is one of the most powerful nuclear nations ^[14].’

In 2016, when then British prime minister Theresa May was asked in parliament ^[15] if she would be prepared to authorise a nuclear strike that could kill 100,000 people, she answered, ‘Yes.’ In 2017, Trump boasted that his nuclear button was bigger and worked better ^[16] than North Korean leader Kim Jong-un’s. The two mocked each other with schoolyard insults and threats and counter-threats ^[17].

In February 2019, after a deadly clash between the two countries’ air forces, Pakistan’s PM Imran Khan warned of the possibility of a nuclear war ^[18]. PM Narendra Modi responded ^[19] that India’s nukes were not reserved for celebrating the fireworks festival of Diwali. After India revoked Kashmir’s autonomy ^[20] in August, Khan reiterated ^[21] that a nuclear war was a real risk. Foreign Minister Shah Mahmood Qureshi repeated the warning ^[22] in Geneva on 10 September. Not to be outdone, Defence Minister Rajnath Singh tweeted ^[23] that India’s no-first-use policy could be shelved under unspecified circumstances.

The more the leaders of the nuclear-armed states revalidate the role of nuclear weapons in their national security, the more they normalise the discourse of nuclear-weapon use and embolden calls for nuclear-weapon acquisition in other countries like Germany ^[24], Japan ^[25], South Korea ^[26] and Australia ^[27].

Instead, the P5 should co-sponsor parallel resolutions in the UN Security Council and General Assembly to reaffirm the 1987 Reagan–Gorbachev declaration. This could act as the circuit-breaker amid the many threatening nuclear storms that are gathering on the horizon.

Why the UN, why both its principal organs, and why the P5?

The UN is the biggest incubator of global norms to govern the world and the vital core of the rules-based global multilateral order. The Security Council and General Assembly play complementary, reinforcing roles. The 15-member Security Council is the world’s only body with the authority to make decisions on war and peace that are legally binding and enforceable on all countries. The P5 can protect their interests with the veto. All of this makes the Security Council the geopolitical centre of gravity of the global order.

But the normative centre of gravity is the 193-member General Assembly, because the UN’s unique legitimacy flows from its universal membership and its policy of one-state, one-vote formal equality in decision-making. The assembly’s adoption of the Treaty on the Prohibition of Nuclear Weapons ^[28] in 2017—against the united opposition of the P5—was an assertion of normative primacy by two-thirds of the international community against the Security Council’s geopolitical dominance.

The chief impact of the nuclear weapons ban treaty is not operational, as none of the countries that voted for it has the bomb, but normative. It dilutes the legitimacy of the continued possession of the bomb by the P5. The major motivation behind the treaty was exasperation at the failure of the P5 to pursue nuclear disarmament. They need to demonstrate nuclear responsibility rather than simply oppose the will of the majority. Otherwise, the already pessimistic mood for the 50th anniversary review conference of the Nuclear Non-Proliferation Treaty next year will deepen even more, threatening the very survivability of this critical anchor of the global nuclear order.

Co-sponsoring identical resolutions in the Security Council and the General Assembly would re-establish the P5’s credentials as responsible nuclear powers without committing them to any concrete course of action.

Its biggest impact would be to harden the normative boundary between conventional and nuclear weapons that has been blurred in recent years with technological developments and serially irresponsible statements on the possession and use of nuclear weapons.