I'm Professor of Practical Philosophy and Knut and Alice Wallenberg Scholar at Stockholm University, where I direct the Stockholm Centre for the Ethics of War and Peace. I work on moral and political philosophy. I am Honorary Chair of the Society for Applied Philosophy.

My work on the ethics of war and self-defence has been published in Ethics, Oxford Studies in Political Philosophy, Proceedings of the Aristotelian Society, Journal of Applied Philosophy, Law and Philosophy, Journal of Moral Philosophy, as two monographs (Defensive Killing, Oxford University Press; The Ethics of War and Peace: An Introduction, Routledge) and in numerous edited collections. I am also co-editor of the Oxford Handbook of Ethics of War.

I am currently writing on a book on the duty to rescue. I have published papers on this topic in Ethics, Philosophical Quarterly and Oxford Studies in Political Philosophy. The latter won the 2019 Marc Sanders Prize in Political Philosophy.

I am also working on the ways in which we can be implicated in other people's wrongdoing. My paper on Wrongful Observation (co-authored with Jonathan Parry) has appeared in Philosophy and Public Affairs. Another, on wrongful assistance, was published in the Journal of Applied Philosophy as part of a symposium on the ethics of indirect intervention. This symposium is part of my project on the ethics of foreign intervention, which is funded by the Knut and Alice Wallenberg Foundation. A third, on moral coercion, was published in Philosophical Studies.

Between 2017 and 2020, I was co-PI on an AHRC project on the status of cultural heritage in war (with Derek Matravers). Derek and I are writing a book on this work, provisionally entitled Stones and Lives: Protecting Heritage in War. An edited collection of papers from the project, Heritage in War: Ethical Issues, is under contract with Oxford University Press.