The US proposal, backed by Britain, for a “cessation of hostilities” in Yemen, to be followed by UN-led peace talks, is welcome. But it raises a number of questions. Why has it taken so long for the Trump administration to act, given that the appalling, avoidable toll on Yemeni lives exacted by the Saudi-led, western-backed bombing campaign has been well documented over the past three years?

Could it be that this sudden burst of American diplomatic activity is linked to last month’s murder by Saudi government agents of the journalist Jamal Khashoggi? In point of fact, there seems little doubt the two events are connected. Donald Trump has shown little or no interest in the Yemen war until now, viewing it as but one of many theatres in a wider, strategic contest between the US, Israel and its Gulf Arab allies on the one hand and Iran on the other. Iran’s backing and arming of Yemen’s Houthi rebels was apparently sufficient reason to turn a blind eye to civilian suffering. In any case, Trump has no appetite for the hard slog of peace-making, as Syrians, Palestinians and Koreans know to their cost.

What Trump is interested in is preserving America’s military, intelligence and economic relationships with the Saudis

What Trump is interested in is preserving America’s military, intelligence and economic relationships with the Saudis and, in particular, with Crown Prince Mohammed bin Salman, who is widely believed to have ordered Khashoggi’s murder. Trump has been at pains to shelter Prince Mohammed from the torrent of international condemnation that followed the Istanbul killing. But he could not stop the furore shining a new spotlight on the Saudi leader’s personal responsibility for, among other bad things, the unfolding catastrophe in Yemen.

Authoritative reports from Washington last week suggest the US has now decided to stick by Prince Mohammed despite the Khashoggi affair. There will be no real punishment. Why? Because Trump needs Saudi support for his destabilisation campaign against Iran, which intensifies on Monday with the imposition of a global oil embargo. Trump sees Prince Mohammed as a key ally, along with Israel, the UAE and Egypt’s dictator, Abdel Fatah al-Sisi, in effecting regime change in Tehran. He also wants to maintain bilateral co-operation on Islamist terrorism, a Syrian postwar settlement, and lucrative arms sales.

But Trump is under growing bipartisan pressure in Congress over the humanitarian disaster in Yemen, for which the Saudis are primarily blamed. Proposed legislation would limit or halt future arms transfers as long as fighting continues. There are also parallel moves to sanction the Saudi regime over the Istanbul murder. So how best to head off the critics, bury the Khashoggi affair and move on? You’ve got it. Switch the focus to Yemen, call a halt to an unpopular war you hitherto ignored and, it’s hoped, regain lost moral ground.

The problems with this cynical approach are numerous and possibly fatal. In their haste to rescue their Saudi client, Trump’s officials do not appear to have consulted, in advance, allies such as Britain. Nobody in Washington seems to have asked the rebels (or Iran) what they think. The US is insisting that, before Saudi bombing stops, the Houthis must first halt their missile attacks, an unrealistic precondition. And it is not even proposing a formal ceasefire, merely an initial “cessation of hostilities”, an altogether different, flimsier idea.

As we said at the start, any halt to the violence in Yemen would be welcome and overdue. But launching into a hazardous peace process for the wrong reasons, on a flawed basis, without proper preparation, in order to serve extraneous, selfish and highly objectionable political ends, invites failure – and may very possibly make matters worse. The UN’s special envoy, Martin Griffiths, now has the unenviable task of implementing the American initiative. We must hope, in the first instance, that the Saudis desist from a new offensive on the besieged port of Hodeidah in the 30 days before the cessation supposedly begins.