The Supreme Court has enumerated the appropriate sources of international law. The law of nations “may be ascertained by consulting the works of jurists, writing professedly on public law; or by the general usage and practice of nations; or by judicial decisions recognizing and enforcing that law.” United States v. Smith, 18 U.S. (5 Wheat.) 153, 160-61, 5 L.Ed. 57 (1820); Lopes v. Reederei Richard Schroder, 225 F.Supp. 292, 295 (E.D.Pa. 1963). In Smith, a statute proscribing “the crime of piracy [on the high seas] as defined by the law of nations,” 3 Stat. 510(a) (1819), was held sufficiently determinate in meaning to afford the basis for a death sentence. The Smith Court discovered among the works of Lord Bacon, Grotius, Bochard and other commentators a genuine consensus that rendered the crime “sufficiently and constitutionally defined.” Smith, supra, 18 U.S. (5 Wheat.) at 162, 5 L.Ed. 57.
The Paquete Habana, 175 U.S. 677, 20 S.Ct. 290, 44 L.Ed. 320 (1900), reaffirmed that
where there is no treaty, and no controlling executive or legislative act or judicial decision, resort must be had to the customs and usages of civilized nations; and, as evidence of these, to the works of jurists and commentators, who by years of labor, research and experience, have made themselves peculiarly well acquainted with the subjects of which they 881*881 treat. Such works are resorted to by judicial tribunals, not for the speculations of their authors concerning what the law ought to be, but for trustworthy evidence of what the law really is.
Id. at 700, 20 S.Ct. at 299. Modern international sources confirm the propriety of this approach.[8]
Habana is particularly instructive for present purposes, for it held that the traditional prohibition against seizure of an enemy’s coastal fishing vessels during wartime, a standard that began as one of comity only, had ripened over the preceding century into “a settled rule of international law” by “the general assent of civilized nations.” Id. at 694, 20 S.Ct. at 297; accord, id. at 686, 20 S.Ct. at 297. 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).
The requirement that a rule command the “general assent of civilized nations” to become binding upon them all is a stringent one. Were this not so, the courts of one nation might feel free to impose idiosyncratic legal rules upon others, in the name of applying international law. Thus, in Banco Nacional de Cuba v. Sabbatino, 376 U.S. 398, 84 S.Ct. 923, 11 L.Ed.2d 804 (1964), the Court declined to pass on the validity of the Cuban government’s expropriation of a foreign-owned corporation’s assets, noting the sharply conflicting views on the issue propounded by the capital-exporting, capital-importing, socialist and capitalist nations. Id. at 428-30, 84 S.Ct. at 940-41.