Business executives have been in a state of limbo over Donald Trump's fluctuating plans to impose major tariffs since he took office in January. Tuesday's announcement does not end that uncertainty. U.

Trump has promoted the tariffs as part of a wider strategy to revive American manufacturing, and as a way to extract concessions from the U.S.' trading partners, adversaries and allies alike. "No room left for Mexico or Canada,

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,