Donald Trump’s 25 per cent tariffs on Canada’s and Mexico’s exports, along with the 10 per cent tariff on China’s, change the world. This is true even though tariffs on the first two countries have been temporarily lifted. We know that, under this president, the US recognises only its own narrow interests as legitimate. That makes it bad. But, worse, its view of its interests is mad. The combination makes it a dangerous partner for other countries to trust.

In Trump’s view, running a trade surplus with another country is a “ripoff”. This is of course the reverse of the truth: such a country provides a greater value of goods and services to US customers than it receives from them. Its residents will either be using this surplus to pay countries with which it is running deficits or be accumulating financial claims, mainly upon the US, because the US is a safe place to invest in and issues the world’s reserve currency. A way to reduce US trade deficits then would be to cease providing highly regarded assets. The inflationary impact of Trump’s fiscal and monetary policies might even achieve that. Yet Trump is determined to retain the dollar’s reserve status. Paradoxically, then, he wants the dollar to be both weak and strong.

Trump’s naive focus on bilateral balances rather than the overall balance (unlike the mercantilists of old) is ridiculous. But it is a reality. So, he is using the threat of tearing up the US -Mexico-Canada Agreement he concluded in his first term to impose penal tariffs. Astonishingly, these tariffs are to be much higher on Canada, with which the US has the longest unguarded border in the world, than on China, its proclaimed enemy. In any case, we now know that being a close ally will not influence Trump. Like any bully, he will menace those he considers weak. It might not end there. Sounding like Vladimir Putin on Ukraine, he has indicated he would like to annex Canada. This is a sick joke. Why would Canadians, with far higher life expectancies and lower murder rates, wish to become Americans?