federal trial

A federal trial is, in US law, a criminal case brought by the federal government against a person for violating federal law — not state law. It is therefore not a case prosecuted by an individual state, but by the federal prosecution service of the United States on behalf of the nation as a whole. In practice, a federal criminal case means that the investigation is typically handled by federal authorities such as the FBI, and that charges are brought by a federal prosecutor — a so-called U.S. Attorney — before a federal court. The proceedings themselves follow federal rules of procedure, and any punishment is determined according to federal sentencing ranges.

In connection with cases such as Sean Combs and Ghislaine Maxwell, the term is used specifically about charges brought under Chapter 117 of Title 18 of the U.S. Code, which deals with transportation for the purpose of illegal sexual activity. The central provision is 18 U.S.C. § 2421, popularly known as the Mann Act, which criminalises knowingly transporting a person across state or national borders with intent that the person engage in prostitution or other criminal sexual activity. When articles about these cases refer to conviction for "Mann Act violations", this refers precisely to a federal criminal case under that provision.

The federal element is decisive: the cross-border transportation — whether between states or across national borders — is exactly what lifts the case from state law into federal jurisdiction. A federal conviction can have far-reaching consequences, including prison sentences imposed under federal guidelines that in certain cases leave the courts limited discretion compared with state systems.