Donald Trump’s strategy comes down to this: win all the white votes. I saw him try it out in an airport hangar in Moon township, Pennsylvania. His arrival was Wagnerian. As heavy rock played, the hangar door slid open to reveal the Trump plane.

The candidate climbed up to the podium and promised a crowd of 12,000 to revoke Nafta, stop the refugee programme, end illegal immigration and bring back coal and steel jobs – to make America great again, “like it used to be.”