New Delhi, July 14 -- As budget surprises go, there was little to beat finance minister Nirmala Sitharaman's 5 July announcement that India would go overseas to partially fund its borrowing plan for the year, setting the stage for the country's first ever sovereign bond issue in foreign currency. The excitement among some investors is palpable. External debt would mean that much less domestic funds would be sought by the government, which in turn would reduce yields in the Indian bond market, help banks pass on policy rate cuts to their loan customers, and ease credit availability to the private sector in general. The added advantage is that interest rates in the West right now are especially low, and so foreign money can be raised quite cheaply-at less than half the domestic rate, by one estimate. With India's overall external debt just about one-fifth of its gross domestic product, over-indebtedness is not a big worry. Yet, it would serve us well not to rush forth with an issue without a close analysis of what it could expose the country to....