New Delhi, April 3 -- After days of uncertainty and speculation, US President Donald Trump announced his promised reciprocal trade tariffs on nearly all countries on Thursday. However, the numbers he used to decide how badly countries should be punished fail a basic smell test. There is little connection between what countries actually impose on US imports and what Trump has accused them of imposing.

This has fuelled speculation that the rates may have been calculated using a simple formula rather than a careful analysis of the complex nature of tariffs, trade and non-trade barriers and currency movements.

The US appears to have derived the tariff rates imposed by other countries by dividing the value of the trade deficit by the value o...