The time on the clock now reads two minutes to midnight (midnight being the symbolic hour of global catastrophe).

This is the closest the clock has moved to midnight since 1953, the height of the Cold War and the same year the Soviet Union tested its first hydrogen bomb.

The move was prompted partly by climate change, but was mainly as a result of developments in the global nuclear environment. North Korea’s repeated nuclear provocations; the absence of any progress on US-Russian arms control; and raised tensions in the Asia-Pacific region have all contributed to a heightened sense of danger. Recent developments will do little to dampen these fears.

Officially released on February 2, the Trump administration’s Nuclear Posture Review (NPR) has sparked fierce debate.

The NPR is a Congressionally-mandated document released by every president (since Bill Clinton in 1994) and it outlines nuclear weapons policy for the next five to 10 years.

Trump looks set to pursue an entirely different, and much more dangerous, approach than previous presidents.

The trend has been a downward trajectory in US nuclear numbers since the end of the Cold War. President George HW Bush enacted an unprecedented number of nuclear reductions in the early 1990s. Post-Soviet Russia quickly followed suit.

While cuts, for various reasons, halted under Clinton, despite his best efforts, his successor, George W Bush (whose administration hardly baulked at the idea of confronting global threats), reduced the US nuclear

stockpile by about half.

It was under Obama that a conceptual change occurred. As president-elect, writing in 2008, Obama said

that he would forge a new path in US nuclear weapons policy, by working towards the elimination of nuclear weapons, going so far as to make this objective a central element of his administration’s policy.

As a first step, he would work with Russia to enact reciprocal cuts. While falling far short of this idealistic goal of disarmament (which he rightly stated he was unlikely to see in his lifetime), Obama’s main legacy was to reposition the idea of nuclear disarmament in the mainstream national security agenda, though as a distant, even aspirational, aim.

While the previous three NPRs sought to engender strategic stability by, effectively, downplaying the role nuclear weapons would play in US policy, Trump’s NPR signals a sharp deviation.

Though tempering much of Trump’s characteristic machismo and bluster, the NPR is a markedly different interpretation of the direction of US policy.

All indications suggest that Trump is seeking to modernise existing weapons, and to expand the arsenal. That would fly in the face of America’s historic commitment to the Nuclear Non-Proliferation Treaty (NPT).

This would also create renewed tensions with “strategic competitors” (ie, Russia and China).

To be fair to Trump, the modernisation programme was ushered in by Obama, as many components of the US nuclear enterprise have, or soon will, reach the end of their service lives.

That said, his approach has raised alarms bells, both at home and further afield.

This new departure should come as no surprise. As president-elect, even before he darkened the doorway of the Oval Office, Trump called for a greatly increased nuclear arsenal, while, apparently, welcoming the suggestion that this would, undoubtedly, spark a renewed arms race.

Amid nuclear sabre-rattling by North Korea, Trump announced that if Pyongyang ever launched an attack on the US (or, presumably, its allies), it would be met with a storm of “fire and fury”, later boasting that his nuclear button was much bigger than Kim Jong Un’s.

Irrespective of the comparative size of Trump’s nuclear button, such crass appeals to masculinity are dangerous in the world of nuclear politics. Veiled (as well as not-so-veiled) threats lead to feelings of insecurity in others, who then take countermeasures to defend themselves.

This, in turn, breeds mistrust and, ultimately, sows the seeds of conflict.

In typical Trump style, his nuclear utterances, mostly communicated through Twitter, have been consistently belligerent and unpredictable.

In a sphere inhabited by diplomats and skilled negotiators (masters in the art of carefully-judged nuance), impulsively tweeting bravado-fuelled nuclear threats simply isn’t done. In any case, many important State Department positions remain vacant, because nuclear diplomacy has been all but ignored by Trump.

According to a Pentagon spokesperson, Trump’s NPR calls for a “credible nuclear deterrent, with diverse capabilities”.

The word “diverse” is subtle, a euphemism alluding to the fact that the president has called for the development of smaller tactical nuclear weapons with lower explosive power.

The thinking behind tactical nuclear weapons is that the current crop is too big and powerful to use as a deterrent, simply because no statesman would regard a threat to use them (for deterrence purposes) as credible.

This, in fact, is a misnomer, since some tactical nuclear weapons possess roughly the same explosive power as the bomb detonated above Nagasaki, which killed 70,000 people.

“Conventionalising” nuclear weapons by making them smaller effectively lowers the threshold for their use and may make a nuclear exchange more likely.

The pursuit of these weapons would also represent a violation of the 1987 Intermediate Range Nuclear Forces treaty (INF), which outlawed an entire category of nuclear missiles between the Cold War superpowers.

While Trump supporters will laud this expansion as part of a wider attempt to “make America great again”, the main issue is, as most sober analysts have argued, that the threat simply doesn’t exist to warrant it. Moreover, he has 4,000 nuclear weapons at his disposal already, and this should be sufficient to handle a multitude of contingencies.

The US nuclear arsenal, for example, far exceeds that of China, in both quality and quantity. It remains roughly on a numerical par with that of Russia, due to the New START arms control agreement, concluded under Obama.

In addition to this, the belief that

Beijing and Moscow are placing nuclear weapons centre stage, as part of their respective defence strategies, is understandable, but mistaken.

To counter this possibility, however, as the review makes clear, the Trump administration wants to widen the range of scenarios under which US nuclear weapons might conceivably be used, such as in response to a cyber-attack or a non-nuclear strategic attack. At the very least, the review indicates that the US will be placing a greater reliance on nuclear weapons in the years ahead.

Not only does the NPR appear to call for an expansion of the US nuclear force, it also actively militates against efforts to reduce nuclear weapons globally. Arms control between the US and Russia is given a derisory mention.

It dismisses the Comprehensive Test Ban treaty (signed by Clinton in 1996, but rejected by the US Senate in 1999). As well as this, Trump has repeatedly criticised the Iran deal, a multilateral agreement concluded between the United Nations P5 and Germany (“P5+1”) and Iran, designed to curtail Iran’s nuclear ambitions, in return for a relaxation of some economic sanctions.

These all have near-universal backing throughout the international community, as a way forward for defusing nuclear tensions, but Trump’s dismissive attitude is a worrying sign.

Jon Wolfsthal, a Harvard academic and former Obama administration official, has stated that the Nuclear Posture Review clearly bears no resemblance to Trump’s actual outlook; rather, he argued, it is a reflection of more moderate voices within his cabinet (namely secretary of defence, Jim Mattis, and secretary of state, Rex Tillerson), whom Wolfsthal calls the “axis of adults”.

The chances of a nuclear exchange are relatively slim. But that’s not to say that it won’t, or can’t, happen. Excessive complacency in the infallibility of nuclear deterrence is misguided, especially with the chatter of loose talk in the background.

As a 71-year-old man, Trump, who would have been an adolescent at the tense zenith of the Cold War standoff, is old enough to remember the Soviet atomic threat, poised to strike the United States at any moment, as well as the now laughable ways in which a vulnerable populace sought to ride out a nuclear attack.

As his policy appears to be moving the United States, and the world, closer to the nuclear precipice, let’s hope the axis of adults continues to prevail.

Jason Douglas is currently pursuing a PhD in US nuclear strategy in UCC