Let’s begin with a short exegesis of humanitarian intervention couched in terms of just war theory (JWT), in order to establish some practical and moral guidelines for the former. Of course, these criteria of action are meant as relatively specific and tight practical and moral constraints for the purposes of establishing the legitimacy of wars before, during, and after conflict and/or humanitarian intervention. As such, no war could claim to be completely just in the sense to be explained below. Even the Second World War, which many consider to be the paradigmatic example of a just war, does not conform to the constraints of JWT criteria, in that it violates some basic requirements of the theory.

Nevertheless, this does not mean that wars and humanitarian interventions cannot enjoy degrees of legitimacy. If we were to insist upon the satisfaction of all criteria, no war in the history or future of mankind could be considered “just” or legitimate. So, the reader is warned that JWT acts something like a regulative ideal or an operative fiction, and wars and interventions can be considered more or less just and legitimate, but never completely so. Nonetheless, humanitarian intervention should not be rejected on the grounds that it will fail to meet the criteria of JWT. The theory itself offers consequentialist and deontological conditions that help those formulating and carrying out humanitarian intervention to bear in mind the morality of that intervention.

As noted above, wars are conducted in three stages: before (jus ad bellum), during (jus in bello), and after (jus post bellum) conflict. We can briefly give an account of some of the principles and norms contained by the first of these three aspects. Jus ad bellum requires that a number of normative considerations be borne in mind, including that the intervening state have a just cause, such as acting in self-defence, protecting citizens of another state from human rights violations perpetrated by their own state, and/or punishment for a wrongdoing that has not been corrected. We should devote more time to this “just cause” requirement, as it requires an account of state legitimacy that is of philosophical interest to us. Firstly, in order to be considered legitimate, a state must be recognised both by itself and the international community.

The consent of the people, or a majority of the people, is evidently vital to its legitimacy, for no state could reasonably make a claim to legitimacy in the face of widespread discontent within its borders and the suppression of signs of discontent. Legitimacy obviously cannot depend on the continuing and overt consent of all citizens. It is enough to say that the majority are not opposed to it, that a minority is not suppressed, and that the procedures, mechanisms, and institutions through which governments are chosen generate outcomes that are seen as legitimate, even though some will disagree with the substantive outcome. Secondly, since the state exists primarily as a set of institutions, procedures, and practices to protect the basic rights of citizens – which can, of course, be interpreted in a variety of ways, at least within certain limits – it is only legitimate to the extent that it carries out this function.

Thirdly and finally, a state cannot violate the rights of other states or the people of other states. Evidently, these three criteria of legitimacy allow us to speak of intervention in the event of any rights violation, even when the state in question violates the rights of its own people, as we could not be morally consistent if we washed our hands of civil war, as well as terrorism. Is it correct to say that for a state to be legitimate that it must also be democratic? According to the brief definition given above, the answer to this question might be No. Legitimacy, according to this understanding anyway, requires only the maintenance of basic rights, general consent, and the understanding of the people that the system is fair. In this case, one’s understanding of the fairness of the procedures for deciding leaders and governments is the determining factor, and not the democratic nature of those institutions per se. However, there is clearly a sense in which a democratically-run state is more legitimate than undemocratic states, to the extent that deliberation is a function of legitimacy, along with other features of the democratic state.