Trying to make sense of the Trump presidency, a quotation from Shakespeare’s Macbeth keeps popping into my head: “A tale/Told by an idiot, full of sound and fury/ Signifying nothing.” Might that one day serve as a suitable epitaph for Donald Trump’s time in the White House? There is certainly a deep longing among the US’s traditional power brokers — Republicans and Democrats alike — to believe that the Trump era is a temporary aberration that may ultimately “signify nothing”.

On a recent tour of American establishment redoubts — taking in Wall Street, Washington and the Kennedy School of Government at Harvard — I encountered a cautious optimism that the Trump phenomenon can be contained, without doing lasting damage to the US. The optimistic case is interesting but also, I think, premature.

The optimists point out that early fears that the president would swiftly undermine American democracy have faded. Mr Trump’s behaviour remains erratic and often outrageous. But it does not look like a coherent plan to subvert democracy. As one Manhattan media type put it, with a mixture of relief and contempt: “Trump lacks the self-discipline to be a fascist dictator.”