As the strikes by the United States, the United Kingdom, and France on Syria last week demonstrate, a select group of countries led by the US are asserting an increasingly broad and controversial authority to use force overseas, on a flawed legal basis. While the issue at stake with the recent Syria strikes is when is it lawful for one country to use force against another, the US and the UK have also argued—publicly and also on a highly dubious legal basis—that they have a broad right to use force in self-defense against non-state actors. But what do other countries think? While the views of the US and the UK have received a lot of attention, the position of other states on an issue important to all members of the United Nations has been much neglected.

Accordingly, it is worth noting the explanation of Brazil’s understanding of the international rules on the use of force against non-state actors offered by Patrick Luna (second secretary at Brazil’s Permanent Mission to the UN, but speaking in his personal capacity) at the American Society of International Law (ASIL)’s annual meeting earlier this month (the full video of the panel discussion is available online, Luna’s presentation starts at 22:52). Luna argued forcefully that international law cannot and should not be changed only by those countries seeking to justify their military operations by reference to expansive and controversial interpretations of long-established core constraints on the use of force.

In recent years the US, the UK, and Australia have all argued that international law permits the use of force in self-defense against non-state armed groups in another country where they unilaterally determine that country is “unwilling or unable” to respond to a broadly defined “imminent” threat. There is widespread concern that these notions threaten to tear apart the long-established and carefully constructed constraints on the use of force under international law enshrined in the UN Charter. An array of commentators with different perspectives have warned that this risks opening the door to pre-emptive action and endangering the international order.

It was clear from the ASIL panel that Brazil takes a very different view from that of the US, the UK, and Australia. In this Brazil is not alone: For example, the Non-Aligned Movement (NAM, a group of 120 states), the Latin American and Caribbean Community group of states (CELAC, 33 states), and Mexico have all issued strong statements expressing concern at the way states have invoked the self-defense exception to the prohibition on the use of force.

Luna’s presentation is an important reminder that all countries have a stake in the issue of the legality of the use of force. Contrary to the notion that the outlier views of a few powerful governments represent the prevailing consensus, this was another indication that a large number of other states have strongly held opposing views that are determinative both for the purposes of establishing the content of customary international law and regarding any changes to the way the UN Charter is to be interpreted.

The positions taken by the US, the UK, Australia and Denmark

Also on the ASIL panel with Brazil were Katrina Cooper of Australia’s Department of Foreign Affairs and Trade, Paul McKell of the UK’s Foreign and Commonwealth Office and Asif Amin of Denmark’s Ministry of Defence. With some important exceptions, McKell, Cooper, and Amin were in broad agreement. Focusing on the use of force against ISIS in Syria, the Australian and UK representatives said that their use of force against non-state actors there is justified in the collective self-defense of Iraq because Syria is “unable or unwilling” to act, while Amin said that while Denmark did not expressly refer to the “unable or unwilling” test in its Article 51 letter, that this would likely form a part of its assessment now. McKell also pointed out how the UK has separately argued that some of its actions—including the August 2015 targeted killing of a UK national in Syria, Reyaad Khan—were justified in the UK’s individual self-defense against a “continuing” and “imminent” threat.

The presentations of the Australian, Danish and UK representatives largely reflected the positions taken by their governments either in public speeches or in letters to the UN Security Council explaining the legal rationale for their military operations in Syria pursuant to Article 51 of the UN Charter. These follow on the heels of a series of speeches and public documents setting out the vaguely defined position of the United States that states are permitted to use force in self-defense against non-state actors where a state is “unwilling or unable” to counter a broadly-defined “imminent” threat. Other states have from time to time invoked similar rationales (for example, see Kenya’s statement on military operations in Somalia, analyzed and critiqued here), although there remain clear distinctions in approach even amongst these states (it is not clear that Denmark, for example, takes the same view on the scope of the concept of “imminence” as Australia and the UK have done, and there are differences between the Australian and UK views).

The “unable and unwilling” test, over-stretched notions of “imminence” employed by the US and the UK, and Australia, and the argument that the use of force may be used in self-defense against non-state actors (and not just states) have all been subject to considerable critique by academics (see, for example, Kevin Jon Heller’s comments on the “unwilling or unable” test, Adil Haque’s posts on “imminence”, Letizia Lo Giacco’s contribution on the use of force against non-state actors; for views in support, see, for example, Jochen Frowein here on non-state actors, or Daniel Bethlehem, here). However, last week was notable for the strength and the clarity with which a state representative critiqued the position staked out so publicly by the US, the UK and Australia.

Brazil’s position

So, what did Luna say? The presentation was rich and complex, and I won’t be able to do it full justice here, but some key points follow:

  1. Emphasis should be on the prohibition on the use of force, not exceptions to it. Article 2(4) of the U.N. Charter prohibits the use of force by one state against the territorial integrity of another. Like all exceptions, the Article 51 right to use force in self-defense should be interpreted restrictively, in a manner that reinforces the 2(4) prohibition rather than undermines it.
  2. Without UN Security Council authorization, the use of force in self-defense against non-state actors is prohibited. Citing a long line of international jurisprudence (of note are the International Court of Justice Oil Platforms and Wall Opinion cases; in Congo v Uganda, the Court remained silent on the issue of whether self-defense was available against attacks by non-state actors) and the absence of support for the alternative in the travaux preparatoires of the UN Charter, Luna maintained that Article 51 permitting the use of force in self-defense must be read in line with Article 2(4) and is only available to respond to attacks by a state or that can be otherwise legally attributed to a state.
  3. The test of “unable and unwilling” is not an accepted legal standard in international law on the use of force. Luna said that an assessment by one country that another is “unable or unwilling” to act against a threat is not a valid consideration when evaluating the legality of the use of force in the territory of that state. Luna also queried the application of this test in Syria, wondering how the different countries could deem Syria as “unwilling or unable” to counter the threat of ISIS when it had consented to Russian operations against ISIS on its territory.
  4. Relying on unilateral assessments of a state’s “willingness” or “ability” to respond can have damaging long-term ramifications for multilateralism and the international order. Luna underscored the risk to multilateralism that stems from interpretations that allow for unilateral assessments of a state’s “willingness” or “ability” to deal with a threat, and the long-term detrimental impact that this may have on the UN Charter and the UN as a whole. A similar concern may also extend to the UK’s invocation of “humanitarian intervention” as a purported legal basis for the Syria strikes last week—as Dapo Akande has explained, “acceptance of the [UK] government’s legal position… would essentially open up the possibility of a small group of states, or individual states, taking action based on their own subjective interpretations as to when it is right or proper to use force.”
  5. There is a risk that this broad legal authority will spread to other contexts, beyond counterterrorism. Luna queried whether states that are arguing they have a broad authority to use force in self-defense, largely forged in the context of counterterrorism, would be used by others to justify strikes against piracy, organized crime, or other perceived threats.
  6. There are risks in expanding the temporal scope of the tests for proportionality and necessity. Luna also highlighted the challenges inherent in operationalizing the concepts of necessity and proportionality as a temporal matter, alluding to concerns about the flexibility of the concept of “imminence” that the US, the UK and others have used as part of their legal justification for strikes. This potentially opens the door to preemptive, anticipatory action against an uncertain future threat, with potentially disastrous consequences for the international order and human rights.

Luna’s presentation echoes Brazil’s official statements on this issue. For example, a key extract from Brazil’s 2017 statement at the UN 6th Committee, the primary forum for the consideration of legal questions in the UN General Assembly, reads:

There are also underlying concerns stemming from attempts to reinterpret the law regarding the content and the scope of self-defense, especially on its applicability in relation to non-state actors. However difficult, we should not shy away from discussing critical legal issues involving the use of force. Some interpretations regarding the scope and content of self-defense arising in counter-terrorism scenarios might not be adequate or advisable, as they might set dangerous precedents. Silence regarding these interpretations, such as the so-called “unwilling and unable doctrine”, should not be understood as acquiescence or as proof of opinio iuris. As the primary forum for the consideration of legal questions in the General Assembly, the Sixth Committee is an appropriate venue for such discussions, which should take into due account the views of the International Court of Justice on the matter.

Formation of customary law and “specially affected states”

Central to Luna’s presentation was the recognition that, while international law evolves and changes, there is a process for its development that must be followed—the law cannot just be changed by unilateral assertions. The number of states that have sent Article 51 letters justifying their intervention in Syria represents a small minority when you consider the full membership of the UN (see here for a collection of official statements by states, including extracts from Article 51 letters).

Implicit in Luna’s comments are concerns about the role of different states in the creation of international law. A number of commentators have criticized customary international law for being an undemocratic process shaped mostly by powerful states to the disadvantage of the interests of developing countries. An oft-cited example is the notion that custom is only made by “specially affected states,” which the U.S. government has asserted are states who engage in the practice whose customary status is at issue, with little regard for the position of states that are distinctly affected by practice. This approach naturally favors powerful states who have the resources, technology and political clout to carry out new and far-reaching actions across borders.

Kevin Jon Heller has argued persuasively that the US approach represents a flawed construct of this notion that has negative consequences for the development of international law. It is not hard to see why the assertion that the only states that get to play a role in the formation of customary law on the use of force are the exclusive club of states using force against non-state actors has been subject to criticism. The implication that states who may be affected by the use of force but don’t know yet are excluded from law-making capacity seems unjust. All states have important interests in the central prohibition on the use of force, and certainly not just those powerful states who have the means to carry out such actions and are asserting their actions to be lawful. It is perhaps notable that the International Law Commission did not make express reference to the doctrine of “specially affected states” in its first set of draft conclusions on the issue of how customary international law is formed.

Silence and consent?

Luna also pushed back on the notion that silence—in the form of a lack of response to Article 51 letters or other public statements—constitutes acquiescence to a particular norm or a new interpretation of a treaty obligation. In Luna’s words “silence can only be used as a basis for changing customary law if states have previously attributed a meaning to [such silence]. And we have not.”

He further highlighted how both academics and a large number of states have pushed back against the interpretation of Article 51 of the UN Charter advanced by the US, UK and others, citing the important but under-referenced NAM statement that “as pronounced by the ICJ [International Court of Justice], Article 51 of the UN Charter is restrictive and should not be re-written or re-interpreted.” Last year, the CELAC group of states also stated that:

We take note with concern of the increase in the number of letters to the Security Council under Article 51 of the Charter submitted by some States in order to have recourse to the use of force in the context of counter-terrorism, most of the times “ex post facto”. We reiterate that any use of force which is not in compliance with the U.N. Charter is not only illegal, it is also unjustifiable and unacceptable. Further consideration should be given in an open and transparent debate on this issue.

Mexico has also taken issue with the way in which states have invoked Article 51 of the UN Charter, warning that such actions run the risk of irregularly widening the scope of exceptions to the prohibition on the use of force under Article 2(4) of the Charter (see here and here, in Spanish).

Yet statements by non-western countries tend to get less attention than the pronouncements of western states. As Michael Akehurst highlighted as far back as 1976, “the practice of some states is more frequent or better publicized than the practice of other states, not because it is intrinsically more important than the practice of other states.”

Is international law on the use of force in self-defense changing?

In their presentations at ASIL, the UK and Australian representatives indicated that they felt there was an increasingly wider acceptance of their view. While some states have adopted similar views, the Article 51 letters on Syria are also striking in their ambiguity, as well as how they diverge on specific points (for more detailed analysis, see Marko Milanovic’s post). Brazil’s contribution last week showed that actually there is strong and significant disagreement, even if it is less well-publicized. Mindful of the risks that Luna outlined, and their own stakes in the international order, it will be interesting to see if other states decide to take more prominent and public positions on these issues.