Pakistan, July 20 -- The most dangerous consequence of India placing the Indus Waters Treaty in abeyance will probably not be a dry riverbed appearing across Pakistan tomorrow morning. New Delhi lacks the reservoirs, canals and diversion works required to stop the western rivers at will. The nearer danger is the disappearance of predictability: water passing through the territory of a hostile upstream state becomes far more threatening when measurements are withheld, inspections cease, project designs are no longer discussed and abrupt fluctuations arrive without explanation.

Michael Kugelman, a Washington-based South Asia analyst, offered the necessary measure of caution in a recent interview. "India is not China. It can't build a huge ...