India, Aug. 11 -- "No power on Earth can stop an idea whose time has come."

When the late Dr. Manmohan Singh borrowed Victor Hugo's words in 1991, India was opening its economy to the world. Three decades later - well after Singh's two-term tenure as India's Prime Minister - the spirit of that moment faces a very different test: what happens when the world starts closing its doors to India?

This past week, US President Donald Trump announced an additional 25% ad valorem duty on Indian goods, effective later this month, lifting effective tariff rates for some items to around 50% once you strip out exemptions.

From an investor's perspective, this isn't just a geopolitical headline. The US is India's single largest export market, $86.5 Bn...