It is useful at this point to distinguish weaker and stronger conceptions of legitimacy. A legitimate state possesses a (claim-)right to exist and to rule. The right to exist entail obligations on the part of other not to threaten its existence in certain ways(e.g. not to attack or to conquer it) A state is minimally legitimate, I shall say, if its right to rule entails that other are obligated to obey it. By contrast, a state is fully legitimate if its right to rule entails an obligation of subjects, or at least citizens, to obey (each valid law). This obligation may be thought of as a general obligation to obey the law, one which requires compliance with every law that applies to one except in circumstances indicated by the la(e.g. justified or excused disobedience). The second, stronger understanding of legitimacy may be the most common one in contemporary discussions. But I think it illuminating to invoke the weaker conception too.