This is a deceptively simple question. It has several possible answers, each of which rests on different (and highly contested) assumptions. In this post I will try to explain what these possible answers are, and what are their implications. I don’t myself know what the ‘correct’ answer here is. It is not my intention to argue for one.

We are grateful for this letter. It raises important and difficult issues. These are issues that must be identified, aired, discussed, specified and further discussed. This letter has spurred such a process. The symposium that the letter objects to focused on the question of the identification of custom in international humanitarian law. It consisted…

Yesterday, the Canadian prime minister, Justin Trudeau, stood up in Parliament and formally accused the government of India of committing a targeted killing on Canadian territory. The victim, Hardeep Singh Nijjar, was a prominent leader of a Sikh separatist movement in India, who was designated as a terrorist by the Indian government. He was assassinated…