In the United States, the Federal Court's power is limited by Article III, Section 2, Clause 1 of the U.S. Constitution:
The judicial Power shall extend to all Cases, in Law and Equity, arising under this Constitution, the Laws of the United States, and Treaties made, or which shall be made, under their Authority;--to all Cases affecting Ambassadors, other public ministers and Consuls;--to all Cases of admiralty and maritime Jurisdiction;--to Controversies to which the United States shall be a Party;--to Controversies between two or more States;--between a State and Citizens of another State;--between Citizens of different States;--between Citizens of the same State claiming Lands under Grants of different States, and between a State, or the Citizens thereof, and foreign States, Citizens or Subjects.
The "cases and controversies" limitation has given rise to a standing requirement that must be met before a U.S. Court may hear a case. The Justiciability Doctrine prevents Courts from providing advisory opinions.
Three Standing Requirements
Before a court may hear a case, the plaintiff must demonstrate that they have "standing." Standing requires proof of all three elements:
Defendant must allege either real injury or must be within the zone of injury.
A case is not ripe if the defendant has yet to suffer injury, or his potential for injury is too speculative. When evaluating whether a given defendant's case is ripe, the court may consider these factors:
- probability that predicted harm will take place
- hardship to parties if immediate review is denied
- fitness of record for resolving legal issues presented.
In order for a court to hear a case, they must be able to resolve the dispute.
A case may be moot if it is too late for the court to hear it. Mootness may be triggered by death, a change in law, or a change in the underlying facts of the case. Failure to prove any one of these elements and the case may be dismissed by the court as non justiciable. In DeFunis v. Odegaard  the Supreme Court concluded that the plaintiff's case against a university that denied him admission was moot because he was later provisionally admitted and was about to graduate by the time the case reached the Supreme Court. Certain cases will never be decided because by the time they reach the Supreme Court they will always be Moot. For instance, by the time Roe v. Wade  reached the Supreme Court, the plaintiff had already given birth. A plaintiff may defeat the mootness doctrine by a showing of: 1)repetition that 2) evades review.
- Voluntary Cessation Rule - Voluntary cessation rule states that voluntary cessation is not grounds for mootness (unless proof of evidence )
- Collateral Consequences - Some injury dissipated, yet some residual aspect of dispute remains. In other words there is SOME redressability still present.
- Class actions - Class Actions cases are permissible despite the fact that some plaintiffs in the class may have moot claims.
Standing may also arise in other situations. A defendant charged with a crime may argue that evidence obtained against them was illegal and should be excluded. However, if they do not have standing to challenge the illegal evidence, it will still be admitted against them.
In addition to the "cases and controversies" requirement, the courts have fashioned several other discretionary limitations which a court may invoke to refuse to listen to an case:
- No Third Party Claims
- No Generalized Grievences
- Zone of Interest Test
- Political Question Doctrine
- DeFunis v. Odegaard, 416 U.S. 312 (1974)
- Roe v. Wade, 410 U.S. 113 (1973)