…at 3:16 AM.  This is well-said (including its description of the positivist view):

All sensible views treat matters of brute social/political fact as partly determining law’s content but some, the nonpositivists, have it that moral judgment is inevitably required in interpreting legal materials to figure out what the law says. Others, the positivists, have it that though moral judgment may well be needed if a judge is to make a decision, it is not required in order to determine what the law (already, before the decision) says; once your interpretation draws on independent moral judgment you are making law rather than finding out its content. I should say that the most important nonpositivist, my late colleague Ronald Dworkin, in his final writings on the topic abandoned what I just attributed to “all sensible views.” He concluded that legal interpretation was moral judgment all the way up and down—that is, matters of social/political fact do not determine any part of law’s content unless there is moral reason for that. I think this kind of view denies the reality of law as a normative order distinct from morality and is mistaken.

Dworkin is certainly the best-known nonpositivist, the one who did the most to deform honest discussion of issues in legal philosophy over the last fifty years; I doubt he's the most important, but that's another story.