repetition, yet evading review." Justice Harry Blackmun wrote that due to the natural limitation of the human gestation period, issues concerning pregnancy will always come to term before the appellate process is complete. Roe v. Wade 410 U.S. 113 (1973). Therefore, the Supreme Court could rule on the constitutionality of an abortion law despite the issue being moot at the time of adjudication. Interpretation The U.S. Supreme Court observed in DaimlerChrysler Corp. v. Cuno (2006): "No principle is more fundamental to the judiciary’s proper role in our system of government than the constitutional limitation of federal-court jurisdiction to actual cases or controversies.” The case-or-controversy requirement of Article III of the constitution requires plaintiffs to establish their standing to sue. Article III standing law is built on separation-of-powers principles. Its purpose is to prevent the judicial process from being used to usurp the powers of the legislative and executive branch of the U.S. federal government. Article III standing requires an injury that is “concrete, particularized and actual or imminent; fairly traceable to the challenged action and redressable by a favorable ruling.” Generally, the clause is taken to mean that a vague, broad injury is not grounds for a federal lawsuit. Relevant cases: Lujan v. Defenders of Wildlife ("[A person] raising only a generally available grievance about government—claiming only harm to his and every citizen’s interest in proper application of the Constitution and laws, and seeking relief that no more directly and tangibly benefits him than it does the public at large—does not state an Article III case or controversy."), Allen v. Wright ("an asserted right to have the Government act in accordance with law is not sufficient, standing alone, to confer jurisdiction on a federal court"), Diamond v. Charles (Article III standing "is not to be placed in the hands of ‘concerned bystanders,’ for use as a ‘vehicle for the vindication of value interests.’"), Arizonans for Official English ("Nor has this Court ever identified initiative proponents as Article-III-qualified defenders of the measures they advocated."), Karcher v. May (Citizens who had standing in their 'public official' roles did not retain standing once they left public office), Hollingsworth v. Perry ("We have never before upheld the standing of a private party to defend the constitutionality of a state statute when state officials have chosen not to. We decline to do so for the first time here"), and numerous other cases. The clause does