Big- league weapon for small- league enemy

The decision to use the United States’ biggest non- nuclear bomb may have been signed off by the commander of US and Nato- led forces in Afghanistan, but it bears all the hallmarks of Donald Trump, US commander- in- chief.

This is a big- league weapon for a small- league enemy.

The GBU- 43/ B Massive Ordnance Air Blast is a 10,300kg weapon of terror.

It was used, we are told, against Isis ( Islamic State) in Afghanistan, to demolish a cave and tunnel complex in the province of Nangarhar.

In so doing, Trump has apparently made good on one of his key campaign promises, prioritising the fight against Isis.

Never mind that this branch in Afghanistan is essentially a rebranded band of militants from Pakistan, with little connection to Iraq or Syria beyond occasional appeals for cash.

Isis has struggled to make inroads in the country and has spent much of its time fighting the Taliban. It was all but defeated.

The tactical value of using such a frightening weapon seems limited. The strategic value is even less.

Instead, it represents the biggest possible demonstration of US might short of using a nuclear weapon. It uses Afghanistan as the backdrop for a fiery message to Russia, North Korea and Syria.

And, at a time when Trump was starting to flesh out a more mature foreign policy, it cannot be coincidence that the “Mother of All Bombs”, as it is nicknamed, was dropped five days after an American green beret, Staff Sergeant Mark R De Alencar, was killed fighting Isis in Nangarhar.

Afghanistan has suffered too much, too long to be used for vengeance in this way.