Preventing an atrocity is a stronger duty than preserving a procedural rule

The argument

This argument shifts attention from the rights of states to the fate of people. Proponents hold that the prohibition on preventive war is a rule of international practice, valuable because it usually produces good results, rather than a moral absolute. Where following it would mean standing by while a regime acquires the means to carry out mass killing, or completes preparations for an invasion, proponents argue that the rule is being honoured at the direct expense of the interests it exists to serve. The argument draws on the parallel of individual conduct. A person who sees an assault being prepared, with weapons gathered and intent announced, is not thought to be obliged to wait for the first blow before intervening; nor is a police force. We treat prevention as better than redress, and we do not regard the aggressor's not having struck yet as conferring immunity. Proponents argue that states are in the same position with respect to their populations, with the difference only of scale, and that the scale strengthens rather than weakens the case. Proponents accept that this reasoning can be abused and argue that the possibility of abuse is an argument about safeguards, not about the principle. A rule that permits nothing in advance of attack does not prevent bad-faith wars, which are launched with pretexts in any case; what it does is disarm good-faith action in the cases where prevention would genuinely have worked. Because the purpose of restricting war is to protect human life, and in some circumstances only early action can protect it, this argument concludes, preventive war can be justified.

Premises

Counter-arguments

Opponents reply that the rule confining war to response against actual attack is not a procedural technicality but the foundation of whatever order exists between states, since it gives every state a condition it can satisfy by not attacking anyone. Once prevention is admitted, no state can make itself safe by peaceful conduct, the rational response is to arm, and the licence claimed is equally available to adversaries with weaker evidence and worse intentions.

Rejecting the premises

[Rejecting P1] That the prohibition is justified by its results rather than held as an absolute is a fair description, and it tells against the argument as much as for it: a rule justified by results is one whose results include whatever follows from announcing exceptions to it. [Rejecting P2] Policing operates under warrant, oversight and subsequent review, and against an identified plan, while a state acting on its own intelligence has none of these. The analogy carries the authorisation that the case it is applied to lacks. [Rejecting P3] The premise is conditional on early action being the only means of prevention and on the mass killing being certain, and both are judgements that cannot be made reliably in advance. As a hypothetical it is persuasive, and it does not describe a situation a government could know itself to be in.