Do we want a world in which the possession of nuclear weapons grants a license to commit aggression? Do we want a world where only formal allies of the United States may feel safe from aggression (if in fact they may)? Do we want a world in which great power conveys legal impunity with respect to war crimes and other crimes under international law? These are among the high stakes raised by Russia’s invasion of Ukraine.

The stakes are strategic, legal, and moral.