CAN Donald John Trump win the US presidency? In any rational political order, that would not even qualify as a question worth asking. This is, after all, a man who thinks the National Inquirer represents serious journalism. Yet our Donald just trounced 16 other Republican candidates for the Republican nomination despite their best efforts to see him off. In fact, Trump has a very good chance of becoming the most powerful politician on the planet this November 8.

Start with the good news. About 77 per cent of the US electorate are women, black, Hispanic or young adults under 35. These are normally taken to be core demographics whom Trump has insulted or disparaged. They represent a modern America that is at heart liberal in the European sense of being centre-left, pluralist and relaxed with itself. A majority of Americans believe in equal pay for women, abortion rights and stronger environmental laws. Believe it or not, polls in the US show the population is in favour of stricter gun controls. And a self-declared socialist just won 22 Democratic primaries, for God’s sake.

However, I went to bed on June 23 thinking – like even my Leave-supporting friends – that the UK had voted to remain in the EU. I have a horrible feeling that much of the same political dynamic that favoured the Leave campaign is going to propel Donald Trump into the White House. Be afraid. Be very afraid.

How will Trexit – America’s exit from political sanity – come about? In England, on June 23, the working class and lower middle class in England voted Leave as a protest against economic and political marginalisation. For the very same reasons, the very same core groups (who are chiefly white) will trump for Donald. They will do so enthusiastically in order to thumb their noses at a system that has presided over their relative impoverishment for decades.

When Trump repeats ad nauseam his mantra of "make America great again", it resonates strongly in the huge Rust Belt of former industrial cities across the north-east of the US, where people feel abandoned and let down. The Trump campaign will focus on four key Rust Belt states – Michigan, Ohio, Pennsylvania and Wisconsin – with 64 electoral college votes. These states traditionally vote Democratic, but each has returned a Republican governor since 2010. Polls show Trump doing well in all four.

Trump’s political ace in the US Rust Belt will be his opposition to free trade agreements – the existing NAFTA treaty with Canada and Mexico, and the proposed TTIP deal with the EU. Hilary Clinton supports both trade agreements though with less enthusiasm of late. During the Michigan primary, Trump stood outside a local Ford plant and announced that if the company shifted production to Mexico, he would impose a 35 per cent tariff on any of its Mexican-produced cars shipped to the US. (Memo to British Brexiteers: you might find negotiating a "free trade" deal with Donald more difficult than you think).

But surely there are still those millions of women, black and Hispanic voters, never mind supporters of the socialist Bernie Sanders, who will turn out in their droves to oppose The Donald. Here we run into a not-so insignificant problem. America might be the land of the free and the home of democracy – but only if you are white. If you are black, or a Mexican immigrant, actually getting registered to vote might prove a trifle difficult.

On Friday, for instance, the supreme court of Virginia struck down a move by the state’s Democratic governor, Terry McAuliffe, to restore voting rights to more than 200,000 convicted felons – who are preponderantly black. In recent years, Republican-dominated states have introduced stringent new voter identification laws. In Texas, to vote, you must show one of seven prescribed forms of proof of identity, including a handgun licence. The Brennan Center for Justice calculates that 17 states will have new voting restrictions in place in November, for the first time in a presidential race.

It’s not that black and Hispanic voters can’t get registered as much as it is discouraging them from doing so by putting up bureaucratic obstacles. In many counties in the southern state of Georgia, local (white) officials have been so artful in impeding voting by the black community that the clock has been set back 50 years to the era of segregation. Result: voter turnout in the presidential election in some states will reach barely 50 per cent. Which gives Trump a big advantage.

Then there is the Hillary factor to contend with. Hillary Clinton will be the first ever woman to head the ticket in a US presidential election. This should be a cause for excitement. Except that Hillary is hardly enthusing the Democratic base, even with a borderline nut representing the Republicans. Nearly 70 per cent of all American voters think Hillary Clinton is untrustworthy and dishonest. In truth she has flip-flopped on issues including gay marriage.

I am not sure there is much evidence that she is uniquely opportunist – she is a saint in comparison to Trump. But Hillary has been around the political block for a very, very long time – and that inevitably breeds voter boredom and disappointment. She is the establishment candidate in this election. No-one can pretend she is anything other than the candidate of Wall Street and the military-industrial complex. Expect Trump to throw lots of mud in her direction.

Yet Mr Trump is open to counter-attack. There are question marks over his exemption from being called up during the Vietnam War. And his business dealings are far from an open book. However, as the Remain camp discovered during the British EU referendum, trashing the opposition does not always produce the planned result. Millions will vote for Donald Trump not because he is a saint, but precisely because they want to attack "the system" – and Donald seems the best man to bring the house down. I suspect many in the UK voted Brexit not caring if it brought a recession that would mainly hurt the rich. After all, if you feel things are going to Hell in a handcart anyway, then lashing out in protest is quite rational.

Nevertheless, there are always consequences – usually for the poor. Donald Trump is a demagogue. He does not really represent the American blue-collar worker or those who have lost out to Wall Street greed.

Trump made himself a billionaire redeveloping America’s decaying inner cities and filling them with high-rise apartment blocks only the rich can afford to stay in. Or by building golf courses and casinos for the leisure class.

Trump is using the anger of ordinary Americans for his own political purposes. If anything, he represents a wing of domestic American capitalism that has lost out to foreign manufacturing competition and is willing to do anything – including outright bullying – to protect its profits. A Trump presidency would add to global instability and raise trade barriers, not lower them.

Certainly, America’s disadvantaged and dispossessed need a voice. But not Donald Trump. The way forward is surely for ordinary Americans to create a new political party independent of both the Republicans and Democrats.