Mutual trust is in short supply between South Asia's two major rivals, India and Pakistan. The nuclear powers are bitterly divided on a host of issues, none more ( seemingly) intractable than the future of Kashmir. Yet, as Rahul Roy-Chaudhury explains, their nuclear arsenals have probably helped steer both countries away from all-out conventional war and even led to a thaw in bilateral relations. The key to better relations in the future will be how effectively India and Pakistan can co-operate to deter non-state actors from carrying out major terrorist attacks.