An important objection to relaxing the rules governing humanitarian intervention under international law is that instances of intervention would multiply as intervention is used as a cover for states to promote their own interests. Historical studies of humanitarian intervention offer a fresh perspective on this argument. Historical precedents have often been overlooked in favour of contemporary cases, which are the overwhelming focus of studies of humanitarian intervention. Scholars project the Westphalian model of sovereignty into past eras, and restrict themselves to a single motivation: the universality of human rights. Only recently have historians begun to discuss cases of intervention from the 16th century forward. The justifications put forward for these interventions were broad, ranging from natural law to protecting the oppressed from tyranny, to confessional solidarity and abolitionism. The value systems of states were reflected in their use of military and diplomatic force and were pragmatically combined with other interests in the countries targeted for intervention. In analysing these historical cases, we come to the conclusion that international law and the non-interference rule have been weaker determinants historically than would appear to be the case to contemporary eyes. Limits on intervention have come from the nature of the international system itself, from pragmatic policies, and from the moral convictions of states, but not from positivist international law, which has mostly been permissive. Although justifications were available, actual instances of humanitarian intervention have been infrequent. These preliminary reflection suggests that if humanitarian intervention is allowed under international law, the number of cases will not rise dramatically but will be held in check by other attributes of the system.
