Bombs are the fool’s gold of war. Imprecise, expensive and cruel, their strategic utility diminishes the farther they fall from a politician’s desk. The US, with Britain in tepid accord, has been bombing unstable Muslim states for 16 years and has delivered nothing but death and anarchy. But the bombs have warmed the souls of successive presidents and prime ministers. A good explosion reaches parts of the body politic no other policy can reach.

Over the last week Donald Trump has seen his stock soar, even among supposed liberals, as he veers from the anti-interventionism of his election campaign and drops bombs on Syria and Afghanistan. Neither country poses the remotest threat to America’s national security. In neither is the US technically “at war”. Both were precisely the conflicts that Trump insisted he would abandon to concentrate on “America first”.

Now the president has tasted the sweet cup of war. A measure of his absurdity is that the beneficiary of the Massive Ordnance Air Blast (Moab) missile dropped on the Afghan mountains will be the local rivals of its alleged Isis victims, the rebel Taliban. It is doubtful that Trump worries about this irony. He just wanted to be seen, as he once put it, to “bomb the shit out of Isis”. He is now so hooked on gesture bombings that he holds a press conference to boast of each one.

The obscenity of the US’s legally questionable power projection is that it wins no battles and gains no territory. Western armies are clearly exhausted by fruitless ground wars in distant parts of the world. As a result, drones, cruise missiles and Moabs are forced to bear the burden of “something must be done”. As the mistakenly bombed civilians of Mosul know to their cost, the targeting is inexact, but the political aim is precise. It is to secure publicity by terrifying distant places with displays of death and destruction.

Trump openly admits that the latest bombing was “to send an important signal to North Korea”. Such signals may be hi-tech, sophisticated and great on television, but they are terrorist all the same. And we have the hypocrisy to accuse others of similar staged gestures intended to change policy by acts of violence.

The US is clearly being led by a one-man wild card whose aides are struggling to bring him under some sort of control. During the cold war, unpredictability in a leader was seen as a powerful adjunct to a nuclear deterrent. It led to a crippling arms race. Are we really back to those days? The only sane response remains to keep a sense of proportion, put on a hard hat and hope for the nightmare to pass. What is baffling is why Britain feels the need to tag along in meek support.