Within seconds of Mr Trump’s statement that he was set to implement them, stockmarkets swooned. The S&P 500 index of large American firms ended the day nearly 2% lower, its biggest fall this year. And the decline probably would have been steeper but for residual suspicion that once the damage becomes evident,

Trump’s tariffs on Canada and Mexico are due to start Tuesday, but the polling and economic dynamics point to political peril.

There are going to be tariffs on Tuesday on Mexico and Canada — exactly what they are, we’re going to leave that for the president and his team to negotiate.” Meanwhile in Mexico: The Mexican government has its own tit-for-tat response to Trump’s complaints about fentanyl smuggling,