What governs the procedure in all civil actions in US district courts?

The procedure in all civil actions in U.S. district courts is governed by the Federal Rules of Civil Procedure. These rules are designed to provide a comprehensive framework for handling civil cases in federal courts, ensuring consistency and fairness in the judicial process. They cover various aspects of civil litigation, including the filing of complaints, the conduct of discovery, pre-trial motions, and trial procedures.

By establishing uniform procedures, the Federal Rules of Civil Procedure facilitate the efficient administration of justice across different jurisdictions, allowing parties involved in civil litigation to understand their rights and responsibilities, thus promoting judicial economy and reducing the potential for procedural confusion.

The other options refer to different sets of rules that pertain to specific areas of law or types of cases, such as state-specific procedures, appellate procedures, or criminal procedures, and are not applicable to civil actions in federal district courts.