Charitable souls may have written off Donald Trump’s nomination of Stephen Moore to the board of the US Federal Reserve as an accident. To follow a week later with Herman Cain, the former pizza king, looks like carelessness. Neither man is remotely qualified to sit in the monetary cockpit of the world’s reserve currency. Both have auditioned for Fed governorships by supporting Mr Trump’s call for monetary loosening. Each would be a thorn in the side of Fed chair Jay Powell, who Mr Trump has been bad-mouthing. Knowing that, Mr Trump’s selections surely qualify as sabotage.

It is one thing for the US president to pack Washington’s regulatory boards with cronies. Every president does it, though Mr Trump far more blatantly than most. It is quite another to vandalise the integrity of the world’s dominant central bank.

In the short term, Mr Powell could handle two dissonant voices. With 12 voting members, the Fed chair could sideline Messrs Cain and Moore even if they took instructions directly from the White House. The danger is that Mr Trump is preparing to remove Mr Powell himself, in spite of having appointed him.