This article is part of our series on Challenges to the Rule of Law in Times of Crisis. Read the series introduction at this link.
America is back in business, and a significant part of its stock in trade is the use of military force. Syria knows as much after being hit by two consecutive administrations in the past four years. Whatever differences Donald Trump and Joe Biden may have in style, demeanour, rhetoric, and politics, when it comes to the use of force their international record so far looks very similar.
Although the US is not formally engaged in an international armed conflict with the state of Syria, over the last years it has deployed military personnel on Syrian territory to stave off the threat of ISIS, and reportedly also to provide a geopolitical counterweight against Russian presence in the region. Moreover, the US has carried out military airstrikes on Syrian territory, most notably in 2017, again in 2018 alongside European allies, and recently on 25 February 2021. Ironically, Trump’s strikes against the Syrian government in 2017 and 2018 were prompted by an ostensible humanitarian rhetoric that is absent in Biden’s justification for his recent decision to strike Iran-backed non-governmental militias operating in Syria.
Indeed, among other grounds such as self-defence and an alleged mandate by the international community, four years ago Trump famously invoked humanitarian concerns in light of the shock produced by the Syrian government’s use of chemical weapons against its own population. Conversely, no chemical weapons were involved this time, and Biden steered clear of such humanitarian rhetoric and stuck to the traditional right of self-defence under the UN Charter to address attacks against US and its allies in Iraq.
This recent strike has been met with immediate condemnation by international law experts, mainly on the grounds that the right of self-defence must be exercised – always in a necessary and proportionate manner – against an armed attack that has occurred, or that is imminent. Since Biden’s strike was carried out ten days after the events motivating it, this US extraterritorial response seems to be too late to qualify as self-defence against an ongoing or imminent threat. Rather, it has been decried as an act of armed reprisal, which is illegal under international law.
Many questions remain to be answered or at least discussed from an international law perspective, bearing on the proverbial who, when and what. These include the legality of the use of force by one single state with no mandate in lieu of the collective security system represented by the UN Security Council; the deterrence of future threats instead of responding to current or past attacks; and the possibility of considering a series of discrete but coherent actions, in this case by non-governmental actors, as a single armed attack under the ‘accumulation of events’ doctrine.
Alongside international law, legal experts have also reflected on the justification for this recent attack under US domestic law, especially considering that this time the battered Authorization for the Use of Military Force or ‘AUMF’ – passed by the US Congress in 2002, its use spanning over two decades of strikes against Iraq, ISIS, and Iranian official Qasem Soleimani – was left on the shelf. Instead, Biden claimed to have direct authority under the US Constitution to conduct the attack.
Thus, the picture legal experts have painted when analysing Biden’s debutant strike is one of plausible justification under domestic law, and of highly dubious lawfulness under international law.
But even if all lawyers agreed that the attack was illegal under both domestic and international law, is the legal rationale the only one we need to take into account to assess Biden’s first use of military force? Is there something else we might say from a moral perspective? Even notorious legal positivists admit there is always room for moral scrutiny beyond the law. This becomes particularly relevant when legal discourse is quickly exhausted, as it is often the case with the scant provisions of international law bearing on the use of force. What will we do when we label an act as illegal, and yet global powers continue to commit it? Will we surrender to the cynicism of realpolitik, or will we fall back to a broader normative language to keep our moral judgments on the ball?
In the case of the use of force between nations, the articulation of such moral enquiries has taken over the centuries the form of the ‘Just War’ tradition, which unfolds into two separate lines of inquiry: when is it justified to resort to armed force (jus ad bellum)? And, what is permitted and prohibited in the conduction of hostilities once the war has begun (jus in bello)? In recent years the discussion has branched out into new avenues, including jus post bellum and jus ad vim (from the Latin vim or ‘force’). The latter was first suggested by Michael Walzer in the preface to the 2006 fourth edition of his canonical Just and Unjust Wars. Reflecting on the controversial invasion of Iraq a few years before, Walzer wrote:
“the Iraqi case invites us to think about the use of force-short-of-war; the containment regime of 1991-2003 that the UN endorsed and the United States enforced is only one possible example of this use. (…) force-short-of-war obviously comes before war itself. The argument about jus ad bellum needs to be extended, therefore, to jus ad vim. We urgently need a theory of just and unjust uses of force. This shouldn’t be an overly tolerant or permissive theory, but it will certainly be more permissive than the theory of just and unjust war.” (p. xv)
And we may add, certainly more permissive than international law, which clearly prohibits any ‘use of force’ by states under article 2(4) of the UN Charter, with very few exceptions (i.e. self-defence and Security Council authorization). But as we saw, the law is not the only framework to analyse instances of the use of force, and some scholars have taken up Walzer’s challenge, laying the groundwork for a new theory of jus ad vim. Among such theorists we find Daniel Brunstetter and Megan Braun, who in 2013 published their influential article titled “From Jus ad Bellum to Jus ad Vim: Recalibrating Our Understanding of the Moral Use of Force.”
According to these authors under jus ad vim a just cause for using force is aggression, whether by states or non-state actors, warranting recourse to the right of self-defence. The use of force must be also proportional, a last resort, authorized by a legitimate authority, and carried out with the right intent (all traditional jus ad bellum criteria). The thrust of their argument is that the use of force must always reduce the probability of escalation. In other words, vim resulting in bellum evidences a failure in the application of the characteristically de-escalatory rationale underlying jus ad vim. As to international law, Brunstetter and Braun argue that jus ad vim should ideally be anchored in that normative regime, but if international law proves to be too narrow to respond to the needs of states, then it will have to evolve through customary law to mirror the evolution of our shared ethical judgments.
Based on the foregoing, can we say that the recent US airstrike in Syria satisfies jus ad vim? There might be some room to argue that US forces and allies were attacked in Iraq and, therefore, that the use of force-short-of-war in self-defence was warranted. And even if we were extremely generous as to concede that the other criteria of last resort, legitimate authority, and right intent were met, a considerable problem from the perspective of jus ad vim remains: however localized and discriminate, such attacks risked escalating hostilities in an already hot and unstable environment. And considering the heavy involvement of Russia in the Syrian quandary, the risk of escalation of the armed conflict to turn into a Cold War-style proxy war between the US (and its allies) and Russia (and its allies) must be an ever-present consideration in every policy decision made by the US, regardless of who sits in the Oval Office.
America is back in business, but for many it just feels like business as usual. Yet, this does not mean that the use of force can continue simply unchecked or that we should surrender to pure realism, for there is a full normative framework in place to assess the legality and morality of such acts under the principles of international law, jus ad bellum and jus ad vim. By using the legal view as a departure point for further moral discussion, the interplay between all these standards offers the potential to strengthen our convictions and hone our judgments about the use of force and war.
Francisco Lobo is a PhD Candidate in the Department of War Studies at King's College, London.
He is a lawyer graduated from the University of Chile. He holds an LL.M. in International Legal Studies from New York University (sponsored by the Fulbright Commission), and a Master of Laws specializing in International Law from the University of Chile. He is a lecturer of International Law, Human Rights Law, International Criminal Law, and Legal Theory, in Santiago of Chile.
He has worked as an NYU Fellow of International Law and Human Rights at the International Law Commission of the United Nations (2018), where he assisted the Special Rapporteur on Peremptory Norms of General International Law (ius cogens), in New York and Geneva. He has also worked as a legal advisor at the Ministry of Foreign Affairs of the Republic of Chile (2019-2020).
His research interests include International Law, Human Rights, the Law of Armed Conflict and the Just War tradition, and International Criminal Law, as well as a multidisciplinary approach to the phenomenon of violence from the perspective of history, philosophy and ethics.