What is the only crime defined in the U.S. Constitution?

The only crime defined in the U.S. Constitution is treason. This definition can be found in Article III, Section 3 of the Constitution, which specifically states what constitutes treason against the United States. It addresses acts such as levying war against the United States or adhering to their enemies, giving them aid and comfort. This precise definition and the constitutional requirements for conviction, which include the testimony of two witnesses to the same overt act or a confession in open court, highlight the seriousness with which the framers of the Constitution regarded this crime.

Other choices like theft, murder, and fraud are not defined in the Constitution and fall under state laws or federal statutes. They do not have the same specific constitutional provisions or rigorous requirements for prosecution as treason does, making treason unique among crimes in the context of the Constitution.