What are federal district courts primarily responsible for?

Federal district courts primarily serve as the trial courts in the federal judicial system, which means their main responsibility is to conduct trials for federal matters. These courts handle a wide range of cases, including civil rights, federal crimes, and disputes involving federal law or parties from different states. They act as the first level of the judiciary where cases are tried, evidence is presented, and witnesses testify.

In contrast, appellate courts, including the federal courts of appeals, handle appeals from lower courts, not trials. This means they review decisions made by the federal district courts rather than conducting trials themselves. The role of district courts is foundational for the judiciary, as they are where the facts of a case are established and legal arguments are laid out in a trial setting.

Additionally, while federal district courts do have criminal jurisdiction, their responsibilities are not limited to criminal cases; they also handle civil cases. Thus, the correct answer emphasizes the broad scope of federal district courts in handling all federal legal matters through trial processes.