Final answer:
Federal courts can make rulings only in response to actual legal cases, primarily through appellate jurisdiction unless involving specific parties or states, and they use precedent to maintain consistency and legitimacy.
Step-by-step explanation:
According to the Constitution, the federal courts can make a ruling only in response to actual legal cases. This means that federal courts are reactive institutions that do not have a mechanism to provide advisory opinions or rule on hypothetical situations. They must wait for a legitimate case to be brought before them. The Supreme Court, in particular, has original jurisdiction in cases involving ambassadors, public ministers, consuls, and where a state is a party. However, most other cases reach the Supreme Court on an appellate basis, where it can overturn or uphold decisions of lower courts. Judicial review allows both federal and state courts to assess the constitutionality of legislation as it pertains to cases in their jurisdiction. Federal cases typically begin in district courts, with the possibility of ascending through the court system to the Supreme Court, subject to the Court's discretion on which appeals to hear.Cases can only be heard by federal courts if they involve a federal law, a constitutional question, a dispute between states, a dispute between residents of different states, or involve international matters. These cases may be criminal or civil in nature. In the U.S., reliance on precedent ensures that federal courts operate with consistency, building on the principles established by prior cases, and contribute to the court's legitimacy as interpreters of the Constitution.