Legitimacy vs. Justification

Oh man, does this ever confuse the hell out of me. Most of the time I can't really see much of a difference between the two; if the State is Legitimate, then it is Justified, and vice versa. But, maybe there is a distinction here, and I've been told that the justification is a matter of degrees, while legitimacy is not. So then, either a State is legitimate or it isn't, and some States can be more justified than others.

This destinction makes it possible to analyse the State at some detail. First, one can determine whether a State is legitimate (i.e. is the State a legitimate form of social organisation), and, if it is, individual States can then be analysed in terms of degrees of justification.

This does, however, seem a little bit backwards. The Morris definition (a State is legitimate if it is just and reasonably efficient) seems to put justification before legitimacy (i.e. if you want to know if a State is legitimate then you must know first if it is just and efficient).

Perhaps most of the confusion seems to come from the fact that both Copp and Morris seem to assume that a state can be legitimate (i.e. the State is a legitimate form of social organisation), and provide non-traditional methods on how legitimacy is then determined. I'm not asking that question. Mine is much more basic, I want to know if the State is a legitimate form of social organisation, no matter the nature of a particular state. I want to know if all possible States (as I've defined the State) can be legitimate.

So, given my ethical approach, my definition of legitimate form of social organisation is one that best/most efficiently promotes eudaimonia (human flourishing), which, as Aristotle seems to think, is the highest moral good.

What am I missing here? Seems way too easy.