With turmoil in the Middle East likely to produce millions of refugees for a long time to come, Europe will have a greater need to protect its borders, intervene abroad and stabilise failing nations. But this will happen at precisely the time America achieves energy independence and is becoming less willing to shoulder the burdens of its allies. The strategic interests of the democracies on each side of the Atlantic could diverge, in a way that has not happened since the end of the Second World War.

In the next few years, British, French and even German leaders, armed forces and security agencies will really have to show they are useful – to defeat the Islamic State of Iraq and the Levant, deter Russia and stop new conflicts from spreading. Otherwise they might find that on an increasing range of issues, they’re on their own.

Trump’s other main policy with an impact on all of us is trade protectionism: he wants to impose swingeing tariffs on imports from China and Mexico, and withdraw from new trade agreements. This would be another disastrous act. It would result in widespread retaliation against American products, higher prices for consumers, and lower growth for the world. For Britain, the ninth largest exporter in the world, such policies would be very bad news indeed.