New Delhi, Sept. 9 -- For decades, emerging economies had reason to envy advanced countries for their fiscal and monetary credibility. Their governments borrowed more cheaply and their sovereign bonds were regarded as safe assets. That distinction is blurring.

The US, UK, France and Japan now confront elevated sovereign bond yields. Large US deficits co-exist with strong growth; Japan faces rising yields after decades of near-zero rates; France and the UK face high debt with difficult fiscal choices. Chinese yields remain unusually low, but this reflects weak domestic demand rather than fiscal strength.

There are lessons for India. First, high public debt can remain manageable for a remarkably long time-until the environment sustaining ...