Neutral States must abstain from supporting a party to a conflict with military equipment and assistance. This core aspect of the law of neutrality has not changed with the adoption of the UN Charter in 1945, or with the brutal Russian aggression against Ukraine. That said, by reviewing the changes to neutrality law over time, this article finds plausible reasons to believe that neutrality has – for better or worse – become optional for the vast majority of States, which can today opt to be non-belligerent States – i.e., States that are neither neutral nor parties to the armed conflict. All States have to cooperate to bring to an end serious violations of international law, including humanitarian law, and this duty of cooperation has abolished “sitting-still neutrality”, but it does not render neutrality law moot. This reading of “optional but not qualified” neutrality maintains the core neutrality idea of abstaining in military matters. In this article, I argue that views of “obsolete” or “qualified” neutrality are not new at all but depart from well-accepted rules of legal interpretation and raise concerns about double standards. Viewing neutrality as optional but unqualifiable offers greater conceptual clarity, is more honest than alternative views, and comes with advantages for humanitarian action.
