I paid my first bribe at 18. As an undergraduate in the late 1980s, I often traveled by train to a library in Lucknow, the capital of Uttar Pradesh, India's most populous state and one of the poorest. Ticketless, like most of the other indigent student travelers, I would follow the ticket conductor on his rounds, trying to dodge him. And then one morning I got caught.

My panicky visions of a few days in some squalid prison lasted all of two minutes. After the exchange of a few meaningful glances, I found myself standing in...