India has threatened before, in other moments of rising tensions, to pull out of the Indus Waters Treaty, which both countries signed in 1960. If India follows through this time, it could restrict the flow of water that is used for most of Pakistan’s crop irrigation and human consumption. Agriculture represents one-fourth of the country’s economy.

As India and Pakistan entered their third day of hostilities, the two nuclear-armed nations remained on the brink of a head-on military confrontation — but how close was difficult to tell, the fog of war made even murkier by tit-for-tat accusations of strikes and false-flag attacks.