How late is it now? On Thursday, the Bulletin of the Atomic Scientists will announce the time on its Doomsday Clock. Last year, the bulletin moved the hands forwards 30 seconds, to reach two minutes to midnight: the closest to catastrophe in six and a half decades. Since then, the immediate peril encapsulated in Donald Trump’s threats of “fire and fury” to North Korea has receded. But Mr Trump should take no credit for pressing pause on a crisis largely of his own making. His actions have exacerbated existing problems on the Korean peninsula, and elsewhere.

As a candidate, Mr Trump is said to have asked why the US could not use nuclear weapons. So it should be no surprise he has proved reckless in office. Last week, his administration announced it would begin its pull-out from the 1987 Intermediate-range Nuclear Forces (INF) treaty next month, and Mr Trump called for billions of dollars of new spending on missile defences. Arms control experts have warned that the missile defence review, and Mr Trump’s rhetoric in particular, risk provoking an arms race, encouraging Russia and China, both of which are potential and actual destabilisers already, to increase their own capabilities.

Meanwhile, Mr Trump has announced he will meet Kim Jong-un for a second summit by the end of next month. Following the Singapore meeting, where he gave away much and received almost nothing, Mr Trump declared there was “no longer a nuclear threat” from North Korea. Yet this week’s missile defence review warned of the “extraordinary threat” it poses. The contrast between the casual jettisoning of the INF treaty, which has kept nuclear weapons out of Europe for 30 years, and Mr Trump’s dangerous grandstanding over the review and summit, is hugely telling.

Making and maintaining such treaties is painstaking and detailed work, and relies on deeply unTrumpian attributes. It requires sustained, strategic, informed diplomacy which appreciates incremental achievements, rather than showpiece events and bombastic announcements driven by whim, vanity, hawkish advisers and, at times, surely, the desire to distract from Robert Mueller’s investigation. It seeks to reach out to adversaries and act consistently towards them; while falling “in love” with Mr Kim, Mr Trump has withdrawn from the Iran nuclear deal. It depends on close cooperation and coordination with allies; Mr Trump reportedly discussed pulling the US out of Nato last year.

Faced with Russian non-compliance with the INF treaty, the US has made no serious efforts to find a solution but has chosen to tool up and announce a free-for-all. Now attention is turning to the New Start treaty, which caps the number of nuclear warheads held by Russia and the US, but runs out in 2021. Its demise would leave no legally binding limits on the world’s largest nuclear arsenals for the first time since 1972. Moscow has said that it would extend it for five years; Mr Trump has called it a “bad deal”.

Allies and parts of the US government have sometimes worked around Mr Trump, notably in taking diplomatic action against Russia. Some hope he could be flattered into promoting a “new” treaty if it was portrayed as a triumph for the great dealmaker. But even if such an approach was possible given the complexity of arms agreements, look at the hawks now surrounding him. James Mattis has quit. The national security adviser is John Bolton, known for his visceral opposition to any kind of constraint on US capabilities. Mr Bolton’s deputy, Charles Kupperman, once suggested it was possible to win a nuclear war.

Last year’s nuclear posture review was summed up as “nuclear weapons are back in a big way”. The new missile defence review proposes investing heavily in questionable technology. One hope is that Congress balks at the huge sums indicated by the two plans. The second is that Europe’s desperate shoring-up of the Iran deal in the face of growing pressure, and its lobbying for an extension or renegotiation of New Start, will pay off. But it will take every ounce of ingenuity and effort that US allies can muster to hold back the hands of the clock.