One of the things political scientists learn over the decades is that very few things in the realm of politics are impossible. Seemingly incompatible states ally, while ideological comrades confront one another. Seemingly solid states and empires collapse with remarkable speed, while weak ones become great powers with nearly equal celerity. Consensuses that war is outdated and anachronistic have been repeatedly proved wrong, as have predictions of victory in war by superior powers. Could another war between China and India happen? Of course, it’s not impossible.

Let’s assume an India-China war would very probably result from a Chinese initiative. China is the superior power and has deeper, more focused grievances toward India than vice-versa. It has fought wars with the US and the USSR, with India and (in the 1930s) with Japan. India’s wars (aside from the Sri Lankan intervention) have all been with Pakistan. So the question can be reformulated this way: when and why might China’s leaders decide war is necessary to punish India?

There...