After Hegemony: The Law on the Use of Force and the Ukraine Crisis

Most questions on the law on the use of force surrounding the Russian invasion in Ukraine are straightforward. There is simply no plausible legal justification for the invasion, and Putin’s attempt at creating one through recognizing the ‘people’s republics’ of Donetsk and Luhansk and then claiming collective self-defence and the need to protect them from Ukrainian ‘genocide’ is obviously baseless. Others have discussed it in more detail, including on this blog (here and here), and it is not necessary to rehearse the argument here.

The case is then one of a great power openly flouting international law, which is shocking for anyone growing up with the idea that Article 2(4) of the UN Charter is a cornerstone of the international order. Historically, however, such a situation is not so surprising – great powers have long sought to evade legal restrictions on their ability to use military force as a political tool. I have tried to capture that in an EJIL piece some time ago. And so perhaps many in Europe were naïve when they believed that military invasions were a thing of the past because the prohibition on the use of force had been sufficiently internalized to rule out war as an option for politics. Perhaps, as many now recognize, the post-Cold War era was more of an interlude, with a stronger genuine commitment to the rule of law for some, while for others restraint was merely strategic and due to their own weakness in the face of Western hegemony. Once that hegemony faded, we could expect that such strategic restraint be abandoned and old ways of power politics return. China’s moves in the South China Sea and Russia’s interventions in its ‘close neighbourhood’ for over a decade have been a warning on the wall. The emphasis on sovereignty and territorial integrity, long a staple in the positions of both countries on international law, may also fade – in fact if perhaps not in discourse – as their capabilities grow.  

The result of this shift may not be so much the death of Article 2(4), memorably diagnosed by Tom Franck already half a century ago, as a demise of the effectiveness of the norm for some powerful actors. The majority of states are likely to continue to defend the rule – for many of them, military expansion is not a practical option and the risk of intervention by stronger neighbours is real. We will probably see a reflection of this in the UN General Assembly later this week. Thucydides’ insight in the Melian dialogue, that “right, as the world goes, is only in question between equals in power, while the strong do what they can and the weak suffer what they must” may not be an adequate reflection of the complexities of world politics today, but it is a healthy reminder that the foundations on which international law rests are, geopolitically speaking, not very firm.

This bifurcated structure – with some openly ignoring rules all others are expected to obey – may be deplorable, but it can also be read as a product of our own approach in the past. I do not think it is necessarily true, as Ingrid Wuerth has argued with a view to Ukraine, that it is the increasing use of human rights and humanitarian considerations that has led to the erosion of the prohibition on the use of force. If properly delimited and coupled with institutional safeguards, the introduction of such considerations could have led to a stable new regime. Yet in a string of contested military interventions in recent decades – from Kosovo to Iraq, Libya and Syria – Western powers have shunned principled and institutionalized constraints and instead used argumentative openness to create space to pursue their aims, even if these aims may sometimes have been laudable. In very few cases have we seen proper attempts at delineating legal arguments. Far too often have governments either provided no legal justification at all or an obviously contrived one, as in the reference to Security Council resolutions with respect to Iraq or Libya, or the stretched self-defence basis for the killing of the Iranian general, Qasem Soleimani. Rather than setting forth a new, principled proposal for interpreting the law on the use of force – as is implied in the notion of a distinct ‘code’, as suggested by Monica Hakimi and Jacob Cogan – intervening governments have often consciously ignored or misconstrued international legal constraints.

One may find Putin’s reference to such instances “a morally corrupt and irrelevant distraction”, as the Board of the European Society of International Law has put it. But as much as this might be true as a matter of moral argument or legal doctrine, it misses a core point about the functioning of international law. Especially in a decentralized order such as international law, the weight of the law is eroded if powerful actors treat it cavalierly. Western governments may have long thought that their own disrespect for Charter rules was inconsequential because of their own hegemonic position – because they had the means to deter or stop others from taking the same latitude. In a changed world order, this is no longer the case, and the insistence on international law by the US and Europe must now look somewhat hypocritical to those who have long been critical of Western interventionism. In today’s multipolar world, maintaining the law on the use of force will require not only decisive responses when others flout the law, but also a readiness to practice restraint oneself. After hegemony, the law requires more careful nurturing or it risks being abandoned not only by a handful of powerful states but also by everyone else.