In case there were any lingering doubts about the sincerity of Donald Trump’s “America First” campaign, he laid those to rest the moment he swore the oath of office. His brief inaugural address was perhaps the most xenophobic in US history.

The 45th president’s one specific foreign policy promise was to eradicate Islamist terrorism “from the face of the earth”. His only other message to the rest of the world was to put it on notice that America would take precedence again after an age in which the US had “defended other nations’ borders” and subsidised their armies.

That age was over, he said. “I will fight for you with every breath that I have,” he promised America. “We will follow two simple rules: buy American and hire Americans.” The rest of the world should be on notice. Mr Trump intends to rip up the US-created global order. His address will go down as a turning point in America’s postwar role — and quite possibly its death knell.