In the United States, a respect for the norms of international law has been part and parcel to domestic law since the framing of the Constitution; “[i]n fact, the Framers held the Constitutional Convention in large part due to the perceived inability of the Confederation to uphold American obligations under international law.”[1]  This was confirmed by the U.S. Supreme Court in the famous 1796 case of Ware v. Hylton.[2]  Significant in the case is a dictum by Justice Samuel Chase:

If Virginia as a sovereign state, violated the ancient or modern law of nations in making the law of 29 October 1777, she was answerable in her political capacity to the British nation, whose subjects have been injured in consequence of that law.”[3]

Here, Chase acknowledges the role played by the shifting norms of international law in the domestic law of the United States.  Both the “ancient” and “modern” norms are binding.  As the norms of international law change and expand with the times, so to does the law of the United States change with them.  And, as we can see by the offhandedness of the dictum, in 1796 this was not a controversial stance.  But the shifting nature of international law is a double-edged sword.  These norms can expand to encompass a broader respect for human rights (and we have seen almost uninterrupted progress in this regard for generations), but likewise there is a danger that the norms of international law can shrink, or regress as nations shirk their international obligations.

Indeed, jus cogens norms can decline as the standards of the international community decline.  But, likewise, these norms of the international community can become stronger and more vigorous, and on the whole the trend has been towards an increasing respect for human rights. Indeed, this is why it is all the more important to protect the ground that has been gained.  If crimes against jus cogens norms are not vigorously prosecuted, we run the risk that the progress made in the cause of human will simply slip away.

In the United States, there had been early attention to a significant number of international crimes that can be committed by private perpetrators and provide universal jurisdiction for criminal or civil sanctions, including piracy; war crimes; breaches of neutrality, territorial infractions, “aggression,” and other crimes against peace; unlawful capture of vessels; the slave trade; violence against foreign ministers and other officials; poisoners, assassins, and incendiaries[sic]; counterfeiters of foreign currency; banditti and brigands; terroristic publications; violation of passports; violation of safe-conducts; and more generally “all . . . trespasses committed against the general law of nations” and the treaties of the United States.

Today, the number of specific international crimes that can be committed by private individuals has increased from earlier categories to include, among others, the following: genocide; other crimes against humanity; apartheid; race discrimination; hostage-taking; torture; forced disappearance of persons; terrorism; terrorist bombings; financing of terrorism; aircraft hijacking; aircraft sabotage and certain other acts against civil aviation; certain acts against the safety of maritime navigation, including boatjacking; murder, kidnapping, or other attacks on the person or liberty of internationally protected persons; trafficking in certain drugs;  slavery;  and mercenarism.[4]

That the poisoners, assassins and arsonists of Vattel’s day might be tried in any court in any country was unlikely; in practice universal jurisdiction was most frequently applied to pirates, and later, slave-traders.
.  Today, these considerations are no longer academic, but practical.  The gains have been tremendous since the post-World War II era; horrendous practices such as apartheid, once carrying the full force of law in many places, is now considered a crime against the human race, punishable anywhere by means of universal jurisdiction.  Such offenders, who could previously be protected by sovereign immunity, now truly know no safe harbor.  In theory, at least.

[1] Ryan Goodman & Derek P. Jinks, Filartiga’s Firm Footing: Federal Common Law and International Human Rights, 66 FORDHAM L. REV. 463 (1997) [citation omitted].

[2] According to the Court in Filártiga vPeñaIrala, 630 F.2d 876 (2d Cir. 1980): “Thus it is clear that courts must interpret international law not as it was in 1789, but as it has evolved and exists among the nations of the world today.” See Ware v. Hylton, 3 U.S. (3 Dall.) 198, 1 L.Ed. 568 (1796) (distinguishing between “ancient” and “modern” law of nations.)” 630 F. 2d at 881.

[3] Ware v. Hylton, 3 U.S. (3 Dall. )199 at 223-4

[4] Jordan J. Paust, The Reality of Private Rights, Duties & Participation, 25 MICH. J. INT’L L. 1229 At 1237-40 [citations omitted].