Even as early as 1900 during the Paquete Habana v United States case, the US Supreme Court ruled,

International Law is part of our law.

The justices, including Chief Justice Gray who is quoted above, ruled that since there has been a long-standing international custom in place, as evidenced by numerous cases and international policies of civilized nations, we ought to follow these rules as well, and rule in favor of the international custom. This is also evidenced by the US Constitution, in which the supremacy clause makes clear that international treaties to which we sign become the “supreme law of the land.”

The case is quite interesting itself, since it puts forth a conclusion that conservatives today still loathe. At the time, the United States was at war with Spain during the Spanish-American war. The Paquete Habana and the Lola were Spanish fishing vessels, or “smacks”, used solely for fishing in and out of Havana, Cuba (Spanish territory). The smacks sailed under the Spanish flag, and unbeknownst to their Cuban crew, sailed into waters which were blockaded by the United States Navy. Both vessels were brought to US territory in Key West and, after a final decree of their condemnation as prizes of war, they were auctioned. In 1898 the court declared it was not satisfied that, “as a matter of law…shipping vessels of this class are exempt from seizure.” Already we see an example of US exceptionalism, since it had been ruled in earlier cases that peaceful vessels were exempt, internationally and domestically.

This decision was reversed in 1900. Chief Justice Gray delivered the majority opinion, reasoning that “International law is part of our law,” and in cases where there is no established treaty or no executive or legislative act, courts must resort to international custom in “civilized nations”. He cites numerous examples of custom where this is upheld in wartime. As evidence of international custom, the court may also pool together the works of jurists and commentators who “by years of labor, research, and experience have made themselves peculiarly well-acquainted with the subjects that they treat.” The customs and practices are sought out in these texts not for what speculations juristic authors might have about law, but for “what the law really is.”

In this case, exempting the fishing vessels was what only seemed fair. It turned out to be an opino juris, an opinion held by many nations as a law and a custom of other nations. Custom expected reciprocity, meaning the US was expected to exempt the vessels. And out of comitas gentium, that is, “neighborliness”, “politeness”, etc., the custom is to be treated as a rule governing prize law and warfare. Needless to say, the comitas gentium was upheld.

It has lately become the opinion of the United States, however, that international opinion is not something that we should seriously consider in lawmaking, or rule-making, or when considering what is the neighborly, or what is the polite thing to do. American Exceptionalism is now the new opinion of our wartime decision-making practices. In 1900, we were a very small player in international affairs. We did not have any veto powers in a body of nations, and thus our opinions were more polite, and more neighborly. If we had treated our enemies with comitas gentium, we reasoned, we should expect the same from them. And therefore, any enemy should be presumed to reason the same way in we had. And we therefore ought to then treat all of our enemies with comitas gentium.

Today we argue that because terrorists are presumed not to be capable of comitas gentium, we ought therefore not to give them any of legal benefits and rights that our enemies, for centuries, have been granted. We ought not give them comitas gentium because we do not see how it could directly benefit us. The writ of Habeas Corpus is one grievous example of a custom that has for a millennium been established and practiced, and is now not granted to our enemies.

As an unimportant player in 1900, our reasoning to comply with international custom was reasoned largely on the basis that it was unconditionally granted to us in the first place. We were simply obliged to comply. But we seem to have forgotten this, and hence we now blatantly contradict the opinio juris of international custom, according to which, we ought to be following the conventions set forth at, for example, Geneva and Brussels. In so doing, we are setting a new precedent, a new custom, to which our enemies are now expected to follow our lead in doing, and which we would simultaneously and hypocritically expect them not to follow. We are expecting comitas gentium, and the orderly obedience to international custom from all nations, when we are simultaneously not following the comitas gentium and the orderly obedience to the customs of nations. Since we now cannot expect our enemies to reason the same way we have in granting comitas gentium to our enemies in 1900, we can expect them to disregard comitas gentium and the customs altogether.

We no longer treat our enemies with this custom, and this, unfortunately, is now to be expected in return.