The Other Carolines

Most readers will be familiar with the Caroline Affair. A group of Canadian rebels seized an American vessel and used it to transport ammunitions from the US to Canada. British forces raided the ship, burned it, killed two men, and sent its wreckage over the Niagara Falls. The incident gave rise to perhaps one of the most frequently quoted maxims in the law of use of force: a state using force in the territory of another must “show a necessity of self-defence, instant, overwhelming, leaving no choice of means, and no moment for deliberation”.

The so-called Caroline Test has been used (and misused) for 179 years. It was referenced both to condemn the German invasion of Norway during World War II and to justify the War on Terror’s expansive views on pre-emptive self-defence and the “unwilling or unable” standard. Very few times is one single set of facts as influential and relevant in the evolution of the law as this one. And yet there is a problem: our lawyerly obsession with it is quite probably based on flawed methodology.

Think about it: what would legal historians of the future make of international law in the 21^st century if they only looked at the diplomatic correspondence between two states in the context of one extremely visible but controversial case? Think about the recent Soleimani case, involving the United States and Iran. Both states produced publicly available documents, including several letters to the Security Council, legal memoranda and, yes, infamous tweets. If 179 years from now, the Soleimani Affair were studied by 2199 lawyers in the same way as legal scholars study the Caroline today, their entire understanding of modern international law would be based on two interpretations of the law that we, the 2020 lawyers, mostly disagree with. It would be, at least, an incomplete picture.

For the Caroline to earn the pedestal it’s been placed on, it needs to make its case that it represented international law back then. Usually, this box is ticked by scholars who note that the US and the UK representatives (Webster and Ashcroft) both agreed on the standard to be used. That both nations were “of the same mind as to the law” is crucial for the Caroline’s pedigree.

This is, however, disingenuous. After all, two states can agree on a wrongful – or at least minoritarian – interpretation of international law. This is exactly the case with the so-called “unwilling or unable test” today. As Jutta Brunnée and Stephen Toope concluded in their excellent study on the matter: “State support for the unwilling or unable standard is much weaker than is often asserted by government officials and commentators. In fact, the purported new rule is supported without caveat by only five States (USA, Australia, Israel, Turkey, UK)”. Judging by its sheer amount of mentions in scholarship, one would not easily reach such a conclusion without a more detailed and thorough review of literature and practice.

Of course, what counted as international law in 1841 is in itself a methodological question. We cannot simply assume that the method for determining international law in 2020 is equally applicable in 1841. The determination of what counted as law in the mid-19^th century involved understanding the interactions between the necessary and voluntary law of nations as well as conventional and customary agreements between states – which is beyond the scope of this blog post. Suffice to say that bilateral agreement was insufficient proof of general applicability. Especially considering that back then approaches to international law were quite diverse: “where the inference from the law of nature is not clear, each nation must be allowed its own interpretation of that law, with the result that in some instances the strict precepts of the law of nature may be evaded”.

But I digress. The point I am trying to make is that for the Caroline Test to be the clear rule we are told it is, its inner logic needed to be not only of general agreement, but also, generally interpreted in the same way. Otherwise it could only count as one possible interpretation of a rule, not the only one. So, was this the case?

Testing this would require a much wider study that I will not undertake here. For sake of brevity, in this post, I will only look at contemporary US views, and compare them in the context of another case, this time with regards to its other neighbour, Mexico. My goal is to raise questions about why international law today is shaped the way it is by an isolated event, outside of the broader context in which it occurred.

In 1836, one year before the events of the Caroline raid and five before the famous Test was ever even uttered, the United States and Mexico were addressing complex issues. Both nations were implementing the 1828 Treaty of Limits, by which a Commissioner would draw a new mutually-accepted border between the two nations. In the meantime, a Treaty of Amity, Commerce and Navigation bound each state to “restrain by force all hostilities and incursions on the part of the Indian nations living within their respective boundaries”.

This was not a simple rule to implement. A year before, Texas, a Mexican province heavily settled by American adventurers, rebelled against Mexico. The US, while partial to the Texan cause, reluctantly declared neutrality and recognised the rebels’ belligerency. By 1836, the rebels had rallied their forces after the events at El Alamo and had exacted a crucial victory at the Battle of San Jacinto. In return, the Mexican Government amassed a new army and marched to Texas. The rebels were concerned that indigenous peoples from the US side of the border might cross into Mexico, join the Mexican army in exchange for land concessions and ultimately squash the rebels with overwhelming numbers. On April 1836, US forces received authorization to preventively cross into Mexico, under guise of the Treaty of Amity. Mexico complained, calling the incursion a violation of US neutrality in favour of Texas. 

Acting Secretary of State Dickins informed the US position to the Mexican ambassador, Manuel Eduardo de Gorostiza, in very blunt terms:

“The present inability of Mexico to restrain the Indians within her territory from hostile incursions upon the citizens of the United States, if they should once be engaged in hostility near the frontier, and the barbarous character of their warfare, which respects neither the rights of nations nor of humanity, render it imperative on the United States to adopt other means for the protection of their citizens. What those means should be must depend upon the nature of the danger. Should that require the temporary occupation of passes beyond the frontier, the duty of self-defence gives them the right to such occupation. It needs no justification but the necessity which led to it”.

The first thing that should come to mind is the difference in language when compared to the Caroline. In full, Webster’s formula required proof. The UK had to “show” the US “a necessity of self-defence”. With regards to Mexico, however, the Dickins formula required “no justification but the necessity which led to it”.

Gorostiza, of course, complained, stating he could not “for a moment admit the existence of such a right [to occupy Mexican land on the basis of self-defence]”. According to Gorostiza this “would be equivalent to acknowledging that every nation might occupy with its troops the territory of another, without taking any further trouble than merely to conceive beforehand that there appeared to be a necessity for this measure”. For Mexico, this was not, by any means, the proper interpretation of the self-defence exception. Indeed, he argued, “[t]his principle [of self-defence] would never have been allowed, were it not, as it is, founded in justice and reason; where it not like all the other principles, together composing the law of nations, derived from the natural law”. Thus, he continued, the right to self-defence “fixes upon us the obligation of preserving and defending ourselves” but, at the same time, “prohibits us from so doing to the evident injury of a third party, unless in a case of absolute necessity, when the danger is imminent, when it cannot be avoided by any other means, and when the injury apprehended is infinitely greater than that which we are about to occasion”.

According to Gorostiza it is clear that none of these conditions were present and that therefore the self-defence exception was not triggered: there was no imminence because the “supposed” indigenous raids “existed only in the imagination of the Texans and their partisans”, and no proportionality because “the mere presence of the troops of the United States should be sufficient to produce embarrassments, dangers, or collisions, which might overthrow the best-concerted plans of the Mexican army”. Absent the strict requirements of the self-defence necessity exception, rather, the US had to remain neutral, respecting Mexico’s “most sacred rights”.

Gorostiza’s position was that of a nation seeking to defend its territorial integrity from an offending neutral. “I may be wrong” – he said presciently to his superiors at the outset of the impasse – “but my opinion is that if we let American troops to enter into our territory as neutrals, we shall sooner or later lose Texas”. A few months later he would again complain that “all this, too, is done in the name of the rights of nations, which are about to be trampled under foot, and with the word neutrality ever on the lip, although neutrality is to be contemned”.

Concern for neutrality and territorial integrity were also at the heart of the US’ position in the Caroline affair. In his address to Congress in 1841, US President Tyler strongly affirmed that “[t]he territory of the United States must be regarded as sacredly secure against all such invasions, until they shall voluntary acknowledge their inability to acquit themselves of their duties to others”. Webster agreed: “[the US government] has held, that however it may have been in less enlightened ages, the just interpretation of the modern law of Nations is, that neutral States are bound to be strictly neutral”.

This was basically Gorostiza’s complaint against the US – that it should not, on account of its duty of neutrality, cross the border, even in self-defence, given the disproportionate harm to Mexico and the lack of imminence. For Webster, in turn, the UK should not have attacked the Caroline, even in self-defence, on account of its duty to respect American neutrality, given the lack of imminence. Comparing Ashcroft’s and Dickins’ responses raises a legitimate question as to who exactly was “of a same mind” with regards to the law. Surely, Gorostiza would have appreciated Webster’s views much more than he appreciated Dickins’. Which itself raises the question of why was the United States assuming different interpretations of the self-defence exception rule in two almost contemporary cases? Likely because the law was not as clear as we have been made to believe. 19^th century law included two differing interpretations of the self-defence exception, one expansive – preferred by invading states – and one restrictive – preferred by invaded states. By the late 1830s, the US simply happened to be both, depending on context.

When seen from the eyes of neutrality and territorial integrity, therefore, the Caroline is not the case of a successful British defence of a broad right to intervention, but rather, a successful American defence of neutrality. This is, in fact, how the Caroline case was understood by contemporary Latin American publicists, increasingly preoccupied with upholding the territorial integrity and self-determination of their newly created republics.

Carlos Calvo, for instance, a profoundly influential Argentinean publicist, noted in 1868, that “M. Webster argued in that occasion in favour of the absolute immunity of neutral territory against the aggression of any belligerent, admitting only the necessity of self-defence as justifiable exception”. Calvo noted approvingly that the United Kingdom yielded to American pressure and offered its apologies for the lack of timely satisfaction. Carlos Wiesse, a Peruvian scholar, also saw the case as a successful defence of neutral territory. Writing in the 1905 Spanish edition of his 1893 book on civil wars, he said: “Continuing pursuit in territorial waters of a third foreign power would constitute a violation of  the latter’s sovereign territory and is therefore forbidden (…) In the case of the Caroline, (…) [t]he diplomatic debate ended with the English government’s apologies for the violation of American territory and for their delay”. In fact, I would dare say Webster himself would be surprised to learn that future American scholars would treat his words not as a defence of American neutrality and territorial integrity but as a reaffirmation of Britain’s more expansive views on self-defence.

The evidence presented should thus, in itself, counsel great caution when using the Caroline maxim as justification for an expansive use of force regime. Not only should it arguably be looked at through the eyes of neutrality and territorial integrity, but, in any case, in conjunction with Gorostiza’s “infinitely greater” standard (which deserves as much interest from modern scholars as Webster’s!).

History is complex, and it is rarely the case that a single event, a single phrase, a single moment in time, will be enough to explain it. As lawyers, we would do well not to engage in what Randal Lesaffer calls a “purely functional” approach to history; that is, to “look at history because [we] need it to better understand current issues and trends”. Before we can learn lessons from it, he says, we have to first “let the past be the past”. In other words, the Caroline can only tell us the story of the Caroline, not of the state of 19^th century international law in general. It is possible, almost inevitable, that just like Gorostiza’s story, there are “other Carolines” lying around in the darker corners of history. Getting to know them, and understanding them all in their own context, may profoundly enrich how we approach our own discipline today. My “novel” idea is, therefore, that we go out and find them.