If Justice Breyer’s statement is a sign that the Supreme Court may now be willing to wrest its “war on terror” role back from the DC Circuit, it may be due not just to concerns about detention policy, but also about the scope of US targeted killings. Even if that’s not the case, whether someone can be deprived of their right to life merely because they were “part of” Al Qaeda or the Taliban, as distinct from having “engaged in armed conflict against the United States” is even more urgent than whether they can be deprived of their liberty.

This is welcome news for those of us who have long argued that mere “membership” in an amorphous non-State entity is hard to define, and can hardly be a sufficient basis for extrajudicial killing. Others have asked pointedly: “Does Al Qaeda even have a ‘non-military’ or ‘political wing,’ like the Irish Republican Army?” That’s a question than needs to be answered before any more people are either detained or targeted.

Gabor Rona is the International Legal Director of Human Rights First and teaches International Humanitarian Law at Columbia Law School.