There are not many laughs to be had from international diplomacy, but US foreign policy in the age of Donald Trump provides a grim kind of comedy all the same. This week the world’s diplomats allowed themselves a chuckle at the risibly inconsistent US approach to Russia, in which the State Department whacks Moscow with sanctions even as the president murmurs sweet nothings into the ear of Vladimir Putin.

When it comes to Russia, the US has become the Jekyll and Hyde superpower. Just three weeks ago, Trump stood next to Putin in Helsinki, unable to utter so much as a word of criticism of the Russian dictator who, a vast body of evidence shows, acted to subvert the American democratic process in 2016. And yet on Wednesday the US announced new sanctions on Moscow as punishment for the attempted assassination of Sergei Skripal and his daughter Yulia in Salisbury with a lethal nerve agent.

What a joke, foreign ministry types will be saying to themselves. The Trump administration is divided against itself, a White House spokesperson only formally endorsing the State Department move a full two days after it had happened. On Friday it emerged that the president’s own national security adviser, John Bolton, plotted with European diplomats to rush through a new Nato strategy document when Trump wasn’t looking – in order to deny him the chance to wreck it and, especially, to soften its tough stance on Russia.