_We are in a uniquely dangerous period in the atomic age. Geopolitical tensions have spiked in Europe, in the Middle East, on the subcontinent and in East Asia. The nuclear arms control architecture is fraying and crumbling, but no negotiations are underway to reduce global nuclear stockpiles.

_

A hostile international security environment, the proliferation of nuclear weapons and the emergence of new space, cyber and AI technologies have increased the risk of accidental or deliberate use of nuclear weapons. The growing strategic risks and uncertainty in turn fuel the vicious cycle of renewed interest among US allies in a nuclear deterrent as a hedge against receding US primacy and reliability.

At the conclusion of a United Nations conference on 7 July 2017, 122 states parties of the Nuclear Nonproliferation Treaty adopted a newTreaty on the Prohibition of Nuclear Weapons. All nine countries that possess the bomb (China, France, India, Israel, North Korea, Pakistan, Russia, the UK and the US) boycotted the conference and rejected the treaty. They have done their very best since then to validate the concerns behind the drive to adopt it.

The2018 USnuclear posture reviewwill guide the Trump administrations nuclear decision-making, modernisation, targeting and signalling. With an expansive vision of the role of nuclear weapons, its threefold effect is to enlarge the US nuclear arsenal, lower the threshold for the use of nuclear weapons, and broaden the contingencies in which the threat of nuclear weapons can be wielded as a tool of diplomatic coercion.

The 2015 Iran nuclear deal established arobust dismantlement, transparency, inspections and consequences regime. Last year, President Donald Trump pulled the US out of the agreement and reimposed sanctions on Iran, despite its still being in compliance with its obligations. That put Washington in breach of the multilaterally negotiated and UN-endorsedJoint Comprehensive Plan of Action. Trumps decision will have reconfirmed North Koreas belief that the one thing standing between its security and a US attack is the bomb. It has also caused the recent surge in tensions in the Persian Gulf.

On 1 February, Trump decided to suspend US participation in the Intermediate-Range Nuclear Forces Treatyan arms control agreement with Russia thatcontributed to the end of the Cold Warand underpinned European strategic stability for three decades. It lapsed on 2 August. Trump has also rebuffed Russian overtures to discuss a five-year extension of New START beyond 2021. His second summit with North Koreas leader Kim Jong-unin Hanoi in Februarycollapsed without agreement and Pyongyang now seems to beexpanding its nuclear arsenal. Still, at least the US and North Korea are engaged in high-level and working-level discussions and the fear of an imminent war has faded.

The altered US nuclear posture will have cascading effects on the arsenals, doctrines and deployments of other nuclear-armed states. On 1 March 2018, Russian President Vladimir Putinboastedof anew array of invincible nuclear weaponsthat can penetrate any defences anywhere in the world. He noted the US had not heeded Russian warnings whenitpulled outof the 1972 anti-ballistic missile treatyin 2002. You didnt listen to our country then.Listen to us now,he said. Putins language wasreminiscent of the Cold War.

After the USRussian suspensions of the INF Treaty,Putin warnedthat Russia could place hypersonic nuclear weapons on submarines deployed near US waters to match the time in which US missiles based in Europe could strike Russia. He also warned of a radioactive tsunami that could be triggered in densely populated coastal areas by a new nuclear-powered underwater drone dubbed Poseidon.

The more that Putin and Trump revalidate the role of nuclear weapons in strengthening national security, the more they normalise the discourse of nuclear weapons use and embolden calls for nuclear weapon acquisition in other countries. In Australia, this debate has been restarted most recently byHugh White.

Meanwhile, the official newspaper of the Peoples Liberation Army hascalled forChina tostrengthen its nuclear deterrence and counterstrike capabilities to match the USs and Russias developing nuclear strategies. China is upgrading its relatively small nuclear arsenal. Itrejected Germanys request to save the INF Treatyby agreeing to trilateralise it, emphasising that its warheads in the low hundreds cannot be compared with US and Russian arsenals in the several thousands.

India and Pakistan are enlarging, modernising and upgrading stockpiles, while investing in battlefield tactical nuclear weapons and systems to counter them. The INF Treaty was the first disarmament agreement of the nuclear age. In an unwelcome symmetry, on 26 February we witnessed the first airstrikes by one nuclear-armed state against another, and the two engaged in a deadly dogfight above the skies of Kashmir the next day.Another IndiaPakistan waris a question of when, not if.

The US, described by former Canadian disarmament ambassador Paul Meyer as the high priest of nuclear orthodoxy, has left its allies looking rather foolish. Washington had led them in dismissing the nuclear weapon ban treaty as impracticable virtue-signalling, instead extolling the decades-long efforts at step-by-step measures to advance the cause of nuclear disarmament that had seen global stockpiles plummet by over two-thirds from their Cold War peak.

When unkind critics noted that the only steps that were visible were leading backwards, Washington responded by launching a new initiative on creating the conditions for nuclear disarmament. Lest some conditions be specified and met, however, Washington suddenly embraced the more nebulous and inherently subjective language of creating an environment for nuclear disarmament.

During the Cold War, Soviet citizens who kept to the straight path as the communist party veered sharply to the left or right were denounced as deviationists. For decades, US allies have been singing from the same hymn book, joining it in the insistence that the step-by-step, progressive approach was the_only_ realistic path to nuclear disarmament. Instead of embracing the new orthodoxy from their fallible high priest, they should do a hard-nosed analysis of the merits of the changing riskreward calculus of integrating more deeply with the nuclear alliance structure or joining the majority of countries in trying to rid the world of nuclear weapons.

Ramesh Thakur, a former UN assistant secretary-general, is emeritus professor at the Australian National University and director of its Centre for Nuclear Non-Proliferation and Disarmament. Image:White House Photographic Office/Wikimedia Commons.