After an amateurish, occasionally shambolic, national convention, Donald Trump accepted the Republican presidential nomination with a promise: when he ascended to the White House in January 2017, “the crime and violence which afflicts our nation will soon come to an end…”

This messianic utterance was delivered in the course of a very long speech in which he veered from endorsing the rights of the LGBT community and equality for women – views associated more with liberal Democrats than the people who comprise his core vote – to avowing the old proto-fascist sentiment “America First”. This mix of what his conservative enemies, like Ted Cruz, call “New York values” and the revival of isolationist rhetoric from the early 20th century seemed to constitute, in the view of many Republicans, a promising start to the presidential campaign.

To the rest of us, it might confirm the suspicion that the man is criminally stupid or the most cynical demagogue in American political history. The very idea that this speech could be seen as some sort of coherent expression of Trump’s rationality tells you everything you need to know. This isn’t funny any more.