US mediation to end Russia's four-year invasion of Ukraine has paused since the Trump administration launched strikes against Iran three weeks ago. Kyiv's response has been to offer expertise to the US and its allies in the Gulf in order to prove itself to be a loyal ally.

Why this war of Donald Trump's choosing? As the death and destruction widen in Iran and around the region, as oil and gas markets take fright, the US president’s reasons for launching what his administration…