In the October 1989 issue of this Journal, I wrote a brief essay concerning the U.S. Constitution and law enforcement abroad. I called attention to the case of Fawaz Yunis, a Lebanese national who was arrested on the high seas by U.S. officers and brought to the United States for trial on charges of aircraft hijacking and hostage taking. Within the space constraints of the Journal’s issue commemorating two centuries of the Constitution, I was able to discuss only one of the questions illustrated by the Yunis case—the question of jurisdiction over crimes committed by aliens abroad. My conclusion, in brief, was that a general reliance on passive personality as the basis for jurisdiction—i.e., the U.S. nationality of victims of the offense—was of doubtful validity under the Constitution, but that jurisdiction based on legislation enacted in implementation of international conventions widely adhered to probably was constitutional. The Yunis case raises two other issues that I believe are of continuing interest: (1) to what extent do the constitutional and statutory restraints on U.S. law enforcement officers apply abroad? and (2) does the so-called Ker-Frisbie rule, according to which a court in the United States may try a person brought before it for a crime over which it has jurisdiction—regardless of how the accused came to be before the court—remain valid and persuasive in the last decade of the 20th century? I want to explore these questions here, bearing in mind that the two questions are related to each other, as well as to the question of jurisdiction to prescribe discussed in the earlier article. Before embarking on the analysis, I want to set forth again in somewhat greater length the saga of Fawaz Yunis, as well as that of two other persons recently seized abroad by authority of the United States for trial in the United States.