Perhaps one day Donald Trump will be dragged out of the Oval Office, his tiny fingernails still dug deep into that fat oak desk. But Trumpland, the country that ignored the politicians and the pollsters and the pundits and gave him the White House in 2016, will outlast him; just as it emerged before he even thought of becoming a candidate. And for as long as it is here it will warp politics and destabilise the US.

I first stumbled upon Trumpland in 2012, a time when it bore no such name and appeared on no maps.

I was reporting in Pittsburgh that autumn, as Barack Obama crushed Mitt Romney while cruising to a second term as president.