  A familiar hypothesis is that the moral concern in play is raised by institutions’ effective power to use force or otherwise coercively to direct citizens’ action. Legality is supposed to constrain or regulate that power, by constituting a necessary condition that demands against persons must meet if they are to be permissibly enforced. Notice that in this role, legality is not a moral filter, a moral constraint on the validity of norms. In the hypothesis in discussion, there is no pool of candidate norms, identified by nonmoral tests, to be put through a further, moral test, before they are pronounced finally valid. Rather, legality is a condition of permissible enforcement of demands against a person, a special moral test that applies to any such demand, including those that are entirely unfounded as well as those that may pass other moral tests. (This is the moral concern, and corresponding role of legality, developed in Dworkin 1986, see also Dworkin 2011. Alternative interpretivist hypotheses might assign to legality a similarly distinctive role in relation to some other moral concern.)