India, Aug. 12 -- US President Donald Trump has hammered a friendly India for buying Russian oil, but spared rival China, another big buyer. He has withdrawn from trade talks with India, and may not attend the QUAD talks that India may host later this year. This has miffed Indian policy-makers. For the past few weeks, officials and commentators have engaged in speculating the reasons behind this arbitrary way of dealing with the two countries. It becomes confusing because the US considers China an enemy, which is capable of challenging its global hegemony.

Democratic India was an ally, at least till the huge tariffs. Not only do the two countries share values but Delhi acts as a counter-balance to assertive China in the Indo-Pacific regi...