New Delhi, Jan. 6 -- Even as extended negotiations go on between Washington and New Delhi on trade, US President Donald Trump seems to have thrown another spanner in the works. On Sunday, he said India could face fresh tariffs if it didn't cut Russian oil purchases. "We could raise tariffs on India if they don't help on the Russian oil issue," he said.

India already faces a 50% US import tariff, half of it imposed as a punitive measure for its crude-oil shipments from Russia. Ironically, this rate has placed Indian exporters at a disadvantage vis-a-vis those of China, with which the US has engaged in an on-and-off trade war under Trump. His latest threat suggests he would have no qualms raising that barrier further.

Of course, this is n...