Political morality governs the reasons the state has for its actions. Private morality governs the reasons an individual has for his or her actions. Political organization governs the structure of the political "agent" that has reasons under political morality (as there are many ways to organize a state, this is a moral question; unlike the organization of the individual agent, which is at least partly a matter of biology). And the political/private interface governs the interactions between the individual and the state.
I really think that this captures all the possibilities. So, I'll close with some examples of how we might adopt different theories in different spheres. One could be a socialist about political morality: the state should act so as to produce the greatest benefit for the state. One could also be a classical rule-utilitarian about private morality: an individual should always act in accordance with the rules that would assure the greatest good for the greatest number. Add in an authoritarian view of political organization: the state should be governed by a single individual holding absolute power. And, finally, a civil libertarian view of the political/private interface: there are limits on how the state can interfere with the individual.
Although these four -- socialism, rule-utilitarianism, authoritarianism, and civil libertarianism -- would be contradictory if applied to the same sphere, they are not contradictory when confined to different spheres. Indeed, one can easily spell out a story to make these four work together as I have described: an absolutely powerful individual ruler must ensure that the state is producing greatest benefit for itself, but is restricted by particular constraints on how he may treat individuals; and, as a private matter, he must ensure that he follows rules that would produce greatest benefit to all. These would be an odd combination, to be sure, but they are not impossible: as each theory has dominion over a different aspect of the moral realm, they can co-exist.
You'll often hear liberals and conservatives trying to adopt a single theory for all spheres at once; which is, ultimately, why I want to push the distinction quite hard. If we keep the distinction between spheres in mind, then it exposes the need for four different sorts of argument for the theory, rather than one "master" argument. Which suggests that we have to be a lot more careful about how we argue for our pet moral views, and provide arguments within each seperate and unique sphere.