One of the most controversial issues in American law today is the extent to which it is appropriate for courts to consider foreign law when deciding issues of United States law. The debate has engaged the courts, Congress, and commentators, leading to discussions about completely banning references to non-United States law by courts. The reality is, however, that the United States courts often have to address or apply foreign law.
Timothy R. Holbrook, Should Foreign Patent Law Matter?, 34 Campbell L. Rev. 581 (2012).