Tensions have been escalating between the US and Iran since May 2018, when Trump announced the US was withdrawing from a nuclear agreement with Iran and was reimposing sanctions on the regime.
The US has blamed Iran for a series of recent attacks on oil tankers in the Gulf of Oman.
In his memo, written at 12.39am UK time on June 22, Sir Kim described disarray and confusion across Washington as Trump unexpectedly aborted the attack.
‘The Administration said nothing for several hours, awaiting guidance from the White House,’ he wrote. ‘Even our best contacts were unwilling to take our calls.’
Sir Kim said the episode illustrated Trump’s ‘aversion to new military adventures’.
But, astonishingly, he made it clear to London that he did not believe the President’s explanation of why he cancelled the attack.
‘His claim, however, that he changed his mind because of 150 predicted casualties doesn’t stand up; he would certainly have heard this figure in his initial briefing.
‘It’s more likely that he was never fully on board and that he was worried about how this apparent reversal of his 2016 campaign promises would look come 2020 [at the next election].’
He warned that this is a ‘divided Administration’ and that ‘it’s unlikely that US policy on Iran is going to become more coherent anytime soon’.
And while Trump had stepped back from the brink this time, Sir Kim warned that the President could still trigger a conflict with Iran, noting that he is now ‘surrounded by a more hawkish group of advisers’.
‘This may, however, only be a temporary pause,’ he warned. ‘Just one more Iranian attack somewhere in the region could trigger yet another Trump U-turn. Moreover, the loss of a single American life would probably make a critical difference.’