the revenue rule, United States courts avoid the application of a foreign sovereign's tax laws" in order to "avoid entanglement with questions about the underlying validity of a foreign sovereign's laws." 268 F.3d at 126. While acknowledging that "the precise scope of the rule" remains an unanswered question of federal law, id. at 109, the court nevertheless determined that "sound policy considerations, including international comity, the proper exercise of sovereign powers, institutional competence and separation of powers, and recognition of the U.S.-Canada tax treaty relationship, support the continuing viability and application of the revenue rule to this case," id. at 126.


71
The First and Second Circuit's recitations of the revenue rule, along with the Supreme Court's understanding of the doctrine, are buttressed by the rule's common law history. AtII.B.,infra, although the Trapilo court correctly summarized the common-law revenue rule, the court erred in its application of the rule. In fact, the court's ruling in Trapilo, which reversed the district judge's decision to dismiss the indictment against the defendants, was called into doubt by the Second Circuit's subsequent decision in United States v. Pierce, 224 F.3d 158 (2d Cir.2000), where the court reversed the convictions of two of the Trapilo defendants. The Trapilo ruling was further limited by the Second Circuit's opinion in Attorney General of Canada, where the court found "the Boots reasoning persuasive" in the context of a civil action, and that, as a result, the circuit's earlier reasoning in Trapilo was "not controlling here." 268 F.3d at 123-24.


2
 In addition to the 13 and