[Editor’s Note:  This is a guest post from Professor Anthony F. Lang, chair in International Political Theory and  Director of the Centre for Global Constitutionalism at the University of St. Andrews.]

Since I wrote my short defence of punitive air strikes against Syria last week in a post at Carnegie Council for Ethics in International Affairs , a number of commentators have given their own, more critical, accounts of this use of military force (see, for instance lots on Duck itself, such as Charli Carpenter; Stephanie Carvin on Opinio Juris ;  , and Dan Kenealy and Sean Molloy in The Scotsman.  I wanted to respond to some of the points made in these posts and elsewhere, not to end discussion, but to continue it. The following are specific issues that have been raised with my thoughts on them:

A punitive air strike would kill more innocent civilians. Certainly, any time military force is used, individuals will be killed. The question for world leaders is whether or not those deaths can be justified. This is precisely what the just war tradition demands; to weigh the dangers of force against the need for justice. The conflict in Syria has resulted in over 100,000 deaths, by conservative estimates, the bulk of which can be attributed to the Syrian government. A punitive air strike will demonstrate to that government such behaviour is not acceptable. It would bring about some semblance of justice in the long term, though not necessarily peace in the short term.

A punitive air strike would not save any lives. The point of punitive air strikes would not be to save lives in the short term. Rather, the point is to punish those who are responsible for using chemical weapons and killing civilians, which would hopefully save lives in the long term. When a criminal is punished in domestic society, the impact could be short term benefit to those harmed (imprisonment), but sometimes it is not (fines imposed). If this use of military force is punitive rather than protective, than the immediate goal will not be saving lives.

(Since I’ve used ‘long term’ twice now, I’m sure someone will respond with the Keynes canard about all of us being dead in the long term. I guess my only response would be that while we might be dead in the long run, the idea of justice won’t be unless we continue to enforce it. That’s the best I could come up with at the moment).

A punitive air strike violates international law. This depends. The obvious way to ensure compliance with international law would be to have a UN Security Council resolution passed. This seems unlikely to happen, however. A punitive air strike might be supported by a generous reading of the Chemical Weapons Convention, in that the convention does not include formal enforcement provisions and Syria is not a signatory to it.

My proposed generous interpretation, though, would be that a ban on chemical weapons is part of customary law that all states are obligated to respect. To enforce this legal rule demands punishing those who violate it. In the end, though, it is unlikely that punitive air strikes can be supported through positive international law so this would require some sort of broader natural law position, perhaps.

A punitive air strike is immoral. This depends on what punitive air strikes are designed to do. If they are designed to reinforce the norm against the use of chemical weapons and to impose sanctions on those who have used them, then there is a moral justification for them, one that relies on a combination of deterrence and retribution. The former is designed to deter other agents in the international order from using such weapons. Whether or not deterrence will work is an empirical question, one that can be investigated through comparison with past instances. Retribution is not quite the same, for it does not rely on a change in behaviour in precisely the same way that deterrence does. It is an attempt to ‘rebalance the scales of justice’. Retribution is sometimes conflated with revenge, but these should not be confused; retribution has a distinguished moral heritage, one that can be found in figures such as Kant and the wider deontological tradition.

Punitive air strikes are not proportional to the use of chemical weapons. As some have asked, hy are chemical weapons worse than any other weapon? Why should we be so exercised about this one? This is an important question and one that is not necessarily clear to me. Banning any kind of weapon seems a good idea, especially one that kills in the slow and gruesome way that chemical weapons do. Further, the use of such weapons has attained a ‘taboo’ status, one that seems wise to reinforce. And, the use of these weapons easily slips beyond the battlefield to infect civilian populations and their resources, such as the natural environment. This is not necessarily a strictly deontological rule, but perhaps more of a prudent one; if we can ban a sort of weapon, and if it requires the use of force to do so, then perhaps this is a good idea. The type of air strikes being contemplated by the US seems proportional as well in that they are very limited.

Punitive air strikes are hypocritical in that they are not always used to punish every violation of every wrong. This is true, but I’ve never found the consistency argument to be quite the trump that some see it as. The US use of force now turns it into a kind of ‘wild west sheriff’ that, while enforcing norms, actually gives it more power in the system. Aidan Hehir and I are currently working on a paper that addresses this problem in the current international order. Our argument is that the use of force to protect ‘norms’ may be morally right in the abstract sense, but it reinforces the power of certain actors. Further, we argue that only by reforming the international legal and political order will this problem be addressed. Russia is making the same argument right now about the US really using this only in order to advance its power. My response to this concern is that, yes, this is a problem. But, if we wait until the political and legal order is revised, such abuses of widely accepted international norms will continue. We need to act now, and work toward changing the system to create a broader, more concrete set of reforms in the coming months and years.

The representatives of the one of the leading states pushing for strikes, the UK, has voted against them. Yes, this is true. And it is even more interesting that in the US, the president has decided to actively consult Congress and in France the president has chosen to allow a debate about this issue (although there may not be a vote). France is particularly interesting because its constitution states that for such uses of force there is no need to consult the parliament, but Francois Hollande seems to have been influenced by Cameron and Obama. While I think the reason the British parliament failed to approve any action was because David Cameron has too many enemies in his own party, the more heartening issue is that in the three leading states on intervention, this question has been put before the representatives of those states. This suggests that there is a deliberative process happening. If anything, the respect for constitutional norms, such as they are, in these three states is one issue for which we can be thankful. How these constitutional decisions domestically impact the global and international constitutional order remains to be seen.