India does not dispute that the risk of nuclear conflict over the next 20 years has increased with the potential emergence of new nuclear-weapon states and the threat that terrorist groups could acquire nuclear materials. Pakistan’s willingness to allow its territory to be used for attacks against India, like the assault on Mumbai in November 2008, inevitably carries the risk of sparking a larger conflagration, and its refusal to sign a “no first-strike” agreement with India is a serious cause for concern.