I think the question of whether the U.N. Charter is law is misleading or meaningless or both, for reasons that I hope this post will make apparent. But now that I have your attention, I want to sketch a few thoughts about the varied reactions to the airstrikes in Syria by the United States, Great Britain, and France.
But is that the end of the matter?
International law is fluid, and “hard” sources of law like treaties can be shaped and even amended by the practice of nations. For example, the U.N. Charter contemplated that the United Nations itself would enforce Security Council authorizations to use force pursuant to military forces provided to it by member states. But these arrangements never materialized, and the relatively rare Security Council use-of-force authorizations are enforced by member states in an ad hoc fashion. Similarly, Article 51 of the Charter says: “Nothing in the present Charter shall impair the inherent right of individual or collective self-defence if an armed attack occurs against a Member of the United Nations, until the Security Council has taken measures necessary to maintain international peace and security.” But through argumentation, interpretation, and practice, this provision came to be seen as permitting self-defensive actions by states in (various modes of) anticipation of armed attacks. Follow-up “measures” by the Security Council have operated unevenly at best.
These examples suggest that the text of the document is not always the last word on lawful uses of force under international law. It is also true that the prohibition on the use of force in Article 2(4) has been violated dozens if not hundreds of times since the U.N. Charter’s creation in 1945. (It is hard to know the precise number since there is so much disagreement on what counts as a violation.) Some people conclude from frequent violations of the U.N. Charter, and the absence of a reliable judicial or executive mechanism to enforce it, that the treaty’s prohibitions do little work in influencing national behaviors. They certainly seem to do little if any work in cases like Ukraine, Crimea, Kosovo and Syria. But violations alone don’t tell the whole story. Many people believe, and it may be true, that there would be many more cross-border interventions but for the norms and enforcement machinery of the treaty. Nobody really knows for sure.
The fluidity and uncertainty about the U.N. Charter’s meaning presents an opportunity for those who want to argue—as they will increasingly do in the wake of the Syria strikes—that its meaning is changing to recognize a humanitarian intervention exception. The document’s text doesn’t support this conclusion. And the “responsibility to protect” doctrine that developed after the Kosovo invasion in 1999 is premised on compliance with the normal rules of the Charter.
Still, proponents of a developing humanitarian intervention will point to Great Britain’s statement about the existence of the doctrine, and assertions by the United States and France that the strikes were “legitimate,” and the very quiet, non-critical reaction by most nations to last year’s Syria bombing, and the fact that only three nations out of fifteen in the Security Council supported the Russia draft Resolution condemning last week’s air strikes, and scholarly support for humanitarian intervention, and so on.
These and related arguments strike me as wholly inadequate, under any theory of international law, to overcome the document’s clear text. (For takedowns of the UK’s humanitarian intervention argument, see this from Marko Milanovic and this from Dapo Akande.) But many people believe that practices and arguments like this can build up to change our understanding of international law, including the U.N. Charter. Perhaps we are on the path to that. I don’t think so, but others disagree, and only time will tell.
Would the development of a humanitarian intervention exception to the U.N. Charter be good or bad? There is a debate about that too. Some people think the scourge of interstate war and armed intervention is worse for humanity than the scourge of human rights abuses—especially when humanitarian intervention, as in Syria, does so little to help the victims of the chemical weapons attack and might spark a broader war with Russia or Iran.
Some people think the opposite. One argument against a humanitarian intervention exception is that once the non-intervention principles of the U.N. Charter are weakened by western nations in the human rights context, non-western nations can ignore those principles to serve their interests as well. Consider Russian Foreign Minister Sergey Lavrov’s invocation of the 1999 Kosovo precedent to justify Russia’s 2014 intervention in Crimea. “If Kosovo is a special case then Crimea is a special case; it’s just equally special,” he said. But did Kosovo really impact Ukraine? Did the weakening of the non-intervention norm in Kosovo make it easier for Russia to grab Crimea? Perhaps, but this is does not seem like a powerful explanation for what happened. A better explanation is that Russia invaded Crimea and the west acquiesced because Russia had local power and was more keenly interested in success, and the west was unwilling to push back because it was insufficiently motivated or organized to confront Russian aggression. International law did not stop the Crimea intervention. But it is hard to show that its violation in 1999 had an impact on its violation in 2014.
The frequent violations of the U.N. Charter, its uncertain impact on the practice of states, the ease with which humanitarian intervention exception arguments are made, and the lack of courts or an executive agency “above” the treaty to interpret and enforce it, lead many—especially outsiders to the debate—to wonder whether the document really functions as law. Such doubts are only enhanced by the frequent claim that some humanitarian interventions are “illegal but legitimate.”
If you are inclined to think that these forms of arguments mean that the U.N. Charter is not “law,” or simply if you are inclined to worry about such things, then please read this article by Daryl Levinson and me. We argue that in many respects, including the respects outlined above, international law is not all that different than that most hallowed form of law, U.S. constitutional law:
Despite superficial appearances to the contrary, constitutional law, like international law, lacks a centralized legislature to specify and update legal norms, and although constitutional courts possess some ability to resolve the existence and meaning of constitutional norms, they are limited in special ways that prevent them from providing authoritative settlement. As a result, constitutional law suffers from the same kinds of foundational uncertainty and contestation over meaning that are viewed as characteristic of international law. Constitutional law also shares with international law the absence of an enforcement authority capable of coercing powerful political actors to comply with unpopular decisions. This lack of an enforcement authority raises doubts about legal compliance and, more generally, the ability of legal norms to constrain and not just reflect political interests. And in much the same way as international law, constitutional law strains to legitimate the limits it purports to impose on popular self-government by invoking various forms (or fictions) of prior sovereign consent.
I know, it sounds crazy. Before you dismiss the argument, please look at it. And ponder this question: Is the Trump intervention lawful under the U.S. Constitution? I seriously doubt that it is. But the truth is that there is contestation about that issue going back to the Founding.
The Framers wanted to put legislative checks on presidential war power. But whether they sought to do so using the declare war clause (and related clauses), or through procedural limits on the standing army, is uncertain. Also uncertain is whether the Article II vesting clause is the locus of broad unilateral presidential war powers. (Again, I doubt it, but many disagree.)
Then there is the question of how much weight to give to text and original meaning, and how much to give to subsequent historical practice. That practice shows a steady growth in the standing army, in presidential war unilateralism (e.g. Korea, Panama, Kosovo, Syria, etc.), and (with the notable exception of the Swiss-cheese War Powers Act) in apparent congressional acquiescence. Congress largely supported the Syria bombing last year, and it seems to support the one last week—however gingerly. Does historical practice plus seeming congressional acceptance, if it is that, confirm the legality of broad presidential unilateralism in war? Does it mean that constitutional meaning has changed? Does it go so far as to support unilateral humanitarian intervention by a president even in the absence of a self-defense rationale? The answers depend on one’s theory of constitutional meaning and constitutional change! On that point, just like on the scope of presidential war powers generally, scholars sharply disagree. And just as with international law, there is no authoritative institution in the United States to settle the matter. In part this is because courts have abandoned the field with doctrines like political question and standing. But the real reason is more fundamental: As Levinson and I argue, courts cannot authoritatively resolve such constitutional law questions.
The constitutional law of presidential war powers is also like the international law of war powers in this respect: It is unclear whether the constitutional law of presidential war power even matters to presidential practice, as legal scholars tend to assume. Many political scientists believe that presidential unilateralism is driven and explained much more, or entirely, by politics—and especially about the relationship between the party that controls the presidency and the party that controls Congress. They may be right.
In short, the uncertainties about the meaning and efficacy of the constitutional law of war powers are similar to uncertainties about the international law of war powers. Indeed, the constitutional limits on presidential war powers are probably more uncertain and contested than the international law limits on the use of force. And the relationship between law and practice in both contexts is largely a mystery. We are largely ignorant about how both grand bodies of law work.