Last month Barack Obama returned to the political stage to deliver a speech about the future of the nation. He did it standing in the Museum of the American Revolution in Philadelphia against the backdrop of a facsimile of the US constitution, which was drafted and signed in that city.

This was not the Obama of old, jacket off, sleeves rolled out, firing rhetorical retorts about hope and change that the world came to know on the campaign trail in 2008. This was a more restrained, somber Obama who barely raised his voice and looked sternly into the camera.

He talked about how the president of the United States should be “the custodian of this democracy”, and how he had hoped Donald Trump would “discover some reverence for the democracy that had been placed in his care, but he never did.”.

He went on to warn that democratic institutions in America were “threatened like never before”. Addressing weary voters tempted not to bother in November’s presidential poll, he told them that Trump and those “who enable him” were “counting on your cynicism … they’re hoping to make it as hard as possible for you to vote, and to convince you that your vote doesn’t matter”.

Then he delivered a coup de grâce: “That’s how a democracy withers, until it’s no democracy at all.”

Barack Obama would say that, wouldn’t he? His speech was a keynote at the Democratic national convention, delivered in support of his friend and former vice-president, Joe Biden.