A friend who was holidaying in Britain at the time of the vote told me of meeting a farmer in Cornwall who had voted for Brexit because he resented the European Union insisting he cut his hedges at the beginning of summer.
Evidently he had no idea why that might be. The only way the EU can justify its farm subsidies in trade negotiations these day is to claim they are paid to keep the rural environment clean and tidy. The subsidies didn't enter the farmer's voting calculation at all, apparently.
Common sense usually prevails without making a close study of these things. Everybody can sense the character of a candidate and leadership they can trust. Brexiteers must have realised their mistake when Boris Johnson and Nigel Farage each took themselves out of leadership contention after the vote. Their work, they decided, was done. They were wreckers, not rebuilders.
Trump's character has been exposed to a hundred million Americans who watched the presidential debates. Those who follow politics more closely and watched the Republican primaries wondered how Hillary Clinton would handle an opponent who operated on his own terms, indifferent to facts, observing none of the polite conventions of presidential politics, infuriatingly obtuse.
She prepared carefully and handled him brilliantly. She didn't get angry, she laughed. Not in the forced way she does in speeches. This time she looked at her supporters in the front row and laughed broadly, naturally. She has never looked better.
She had only to prod Trump occasionally and let him spew his bile and bullshit. "Wow," she grinned after one heavy dump on her in the first debate. It was exactly the right way to reach voters who find Trump immensely entertaining, sharing many of his sentiments, heartily enjoying what he says but knowing all along it is reckless and dumb.
Brexit, I suspect, was a sobering experience for voters everywhere, a reminder that voting is not the same as venting an emotion or sending a signal of discontent. Voting is a powerful decision, with consequences.
When Americans vote on Tuesday, they have the welfare of all of us in their hands. Trump may not know what he is talking about when he damns every trade deal the US has done but he means it.
The only business he knows is real estate. He runs a private company, not answerable to shareholders and directors, holding all the cards in deals with contractors, paying no federal income tax and proud of it, pleasing himself with products branded for himself.
He has never been a trader, has no sense of reciprocal benefit. For him, trade means winners and losers and if the US concedes anything in a deal it is the loser in his mind.
This is the one subject on which he has been consistent in his view for decades. If he gets in, the shutters will go up, not just in America but in retaliation by China, Japan and other leading economies.
Tariff walls and the like would do far more widespread damage than any wall he might erect against illegal immigration.
If Trump wins, it will be mainly because of immigration, as it was with Brexit. The tide of people pressing into Europe last year created images that scared Western democracies more than has been reported.
Media reports treat the migrants as refugees seeking safety, when it is plain to every television view that they are already out of danger and demanding entry to the country of their choice. But their access is being controlled and, like all developed economies with ageing populations, the US needs immigrants. It doesn't need Trump.
If he wins, commentaries will try to make the result respectable, blaming "globalisation", static incomes, inequality, the loss of rustbelt jobs. Don't believe it. Rustbelt jobs disappeared a generation ago. The US economy is creating plenty of jobs. If he wins it will be because he represents how most Americans think. How embarrassing that would be for the rest.
