A traditional way to characterise the norms that govern the laws of war is that between ‘ius ad bellum’ (the right to engage in war) and ‘ius in bello’ (the law of armed conflict, i.e., the right which applies in a state of war). At first sight, these notions may seem unproblematic, at least semantically. They seem to simply refer to the rules that determine the circumstances under which one is absolved of any fault for belligerence, and those that stipulate how one should act once a state of war is a reality. Serious problems emerge, however, once the status of these rules is critically examined.
In qualifying certain acts as conflicting with ‘ius in bello’, one is left to wonder to what such a phrase amounts. ‘Ius in bello’ implies the possibility to judge whether the rules in a state of war have actually been observed, which, in turn, implies the existence of an authority that is to act as the court of justice. In what follows, I will argue that the problems with such a stance are twofold.
First, this state of affairs conflicts with the nature of war, which is, by definition, characterised by the absence of rules, or at least the non-observance of rules if they are presumed to exist. This may appear to evidence a dogmatic stance on my part with regard to the meaning of ‘war’: why should war by definition be characterised by a lack of rules? I would argue that the observance of (enforceable) rules to mitigate or even resolve the conflict is a sign of the war already being at an end. Second, it presupposes the fact that the transgressor acts upon the possibility that at some point in the future, the war will end, whereupon the defeated party (presuming that this is also the party that has failed to act in accordance with the rules) will be judged. For simplicity, I will hypothesise a two-party conflict. Several parties may be involved, and various conflicts may constitute a war, but that does not affect the present line of reasoning.
In situations of ‘ius in bello’, the transgressor is not judged before the war has ended. This follows from the fact that a judgment would make no sense prior to the war’s conclusion; a minor additional reason would be that it would not at that stage be clear whether all relevant acts that are to be judged can be brought to the fore since additional perpetrations may take place in the course of the, ex hypothesi, ongoing war. Once the war is over, a victorious transgressor will still not be judged unless the conflict is limited to a relatively small territory and/or a small number of people, in which case one or more outside parties may serve as judge(s), which is predicated on the power of the party that is to be judged being limited to such an extent that a judgment against it will carry actual consequences. The issue of enforceability is manifest at this point. Whether the appointment of judges that must take an objective stance, exemplified by the International Criminal Court, may be said to result in a de facto vicarious ruling by the victorious (rule-observing) party, amounting to a veritable ‘Siegerjustiz’ (victor’s justice), is an issue that is worth mentioning here, but it is not inextricably linked to the matter at hand.
In any event, it can be argued that ‘ius post bellum’ (the law after a war) is a more appropriate phrase to characterise the situation than ‘ius in bello’. The Geneva Conventions, for example, only make sense if (1) parties observing the rules take into account the possibility that they will lose the war (thus already contemplating the ‘post bellum’ reality, and incorporating it into their considerations), while (2) there is an organisation with enough power to – eventually – enforce the rules laid down therein (which constitutes the ‘ius’ part of the phrase, demonstrating, incidentally, the difficulties involved in enforceability at the international level).
Parties may proceed from the presumption that they will be victorious, or that the war will never end. Under this presumption, they may take into consideration the temporary cessation of violent activities even where a (stable) state of peace is not taken to be a viable outcome. In that case, the ‘ius’ either (1) cannot have concrete effects (the victorious party not acknowledging an international court of justice, which is a relevant factor if it cannot enforce its verdict), or (2) can never be taken to refer to a real state of affairs (since the state of war, ex hypothesi, does not reach an end).
On the basis of the foregoing, I venture to suggest that ‘ius in bello’ cannot be maintained as it involves a contradiction in terms, and must be replaced by ‘ius post bellum’. Basically the same analysis applies to ‘ius ad bellum’, since here, too, acts can only be assessed after the state of war has come to a conclusion. The only slight difference with ‘ius in bello’ might be taken to consist in the fact that parties that appeal to ‘ius ad bellum’ can be judged without a state of war ever actually being reached in the first place. This is the case in the situation in which they conform to the rules because they acknowledge the rules’ legitimacy, on that basis desisting from any belligerent acts. Even in this case, however, the question arises whether they do not simply abstain from such acts on the basis of a cost-benefit analysis (or, if this sounds too cynical, an analysis that is not, in any event, based on ‘moral’ considerations), so that even the existence of rules would not be a relevant given.
In the most consistent interpretation, then, ‘ius in bello’ and ‘ius ad bellum’ are dissolved into ‘ius post bellum’, the latter remaining the only potentially viable notion. I say ‘potentially viable’ since its presence still points to the existence of ‘international law’ as a significant domain of law. I do not presume to be able to address all relevant aspects of this issue here, as the room to do so to the extent the subject matter would require does not suffice. This is not my version of the escape notoriously used by Fermat (commenting on his last theorem), as I have dealt with the topic in some detail elsewhere, but merely a reflection of my awareness that limitations to discussions such as the present one are necessary, so as not to tax the reader (presuming, hopefully not inappositely, that this point has not already been reached). Suffice it to say that the absence of enforceable rules does not contribute to the convincingness of the position of those who contend that international legislation should be considered a counterpart of legislation at the national level.