...it is the way the escalations mimic war simulations held over the years. Spooks and scholars have conducted many mock conflicts between the two countries, with specialists playing the parts of leaders on each side. Very frequently the result is nuclear war. In conversations with experts, including those who launched nuclear strikes in these war games, the precariousness of the South Asian nuclear balance is clear. Paradoxically, the tiny number of nuclear weapons on each side creates instability and an incentive to launch a first strike — use your arsenal or lose it.

Now, I don't really think that another war will erupt between India and Pakistan, or that if it does it will go nuclear. Essentially what is happening is that the Indian government is huffing and bluffing, both for domestic political gain and to scare Pakistan into making concessions. As Stephen P. Cohen, an American scholar, puts it: "The Indians are escalating the crisis to an international level. They see this as a good opportunity to press Pakistan."

But the risks are so cataclysmic that Washington must do more, partly by extracting concessions from Pakistan but mostly by emphasizing to India that it must come to its senses and stand down.

The nub of the problem today is that India is behaving as if it and Pakistan were still two-bit countries. Talk to Indian officials and journalists, and the same refrain arises: Americans are destroying terrorists in Afghanistan and Israelis are swatting militants in the West Bank, so why can't we whack Pakistan for the attack on our Parliament building?...