cases and controversies

the judicial power vested by Article 3 of the Constitution in this Court and the inferior courts of the United States established by Congress thereunder, extends only to 'cases' and 'controversies' in which the claims of litigants are brought before them for determination by such regular proceedings as are established for the protection and enforcement of rights, or the prevention, redress, or punishment of wrongs; and that their jurisdiction is limited to cases and controversies presented in such form, with adverse litigants, that the judicial power is capable of acting upon them, and pronouncing and carrying into effect a judgment between the parties, and does not extend to the determination of abstract questions or issues framed for the purpose of invoking the advice of the court without real parties or a real case.