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.
Prohibition on Advisory Opinions
The Justiciability Doctrine prevents courts from providing advisory opinions.
Article III of the constitution prevents courts from providing advisory opinions. Courts are reluctant to provide advisory opinions for several reasons:
- Reluctance to provide advisory opinions that could then be overridden by Congress.
- Judgments are better made over actual facts.
- Reluctance to do the jobs of other branches.
- Act of advising seems overly-legislative.
Declaratory judgments should not be confused with advisory opinions.
Before a court may hear a case, the plaintiff must demonstrate that they have "standing." Standing requires proof of all three elements:
- Injury - Defendant must allege either real injury or must be within the "zone of injury."
- Causation - The injury must be caused by the defendant.
- Redressability - The court must be able to provide a remedy to the defendant.
Standing may also arise in other situations. A defendant charged with a crime may argue that evidence obtained against them was illegally obtained and should be excluded. However, if they do not have standing to challenge the illegally obtained evidence, it will still be admitted against them.
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 any of these three factors:
- Probability that the predicted harm will take place
- Hardship to parties if immediate review is denied
- Fitness of record for resolving legal issues presented.
A case may be moot if it is too late for the court to hear it.
Mootness may be triggered by the following:
death, a change in law, or a change in the underlying facts of the case.
If the case is moot, it will 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 a claim that is 1. repetitive, that 2. evades review.
- Voluntary Cessation Rule - This rule states that voluntary cessation is not grounds for mootness (unless proof of evidence)
- Collateral Consequences - This doctrine exists when some injury is dissipated, yet some residual aspect of a dispute remains. In other words, there is some redressability still present.
- Class actions - Class action lawsuits are permissible despite the fact that some plaintiffs in the class may have moot claims.
In addition to the "cases and controversies" requirement, the courts have fashioned several other discretionary limitations which a court may invoke to refuse to hear to a case. These limitations are not based on Article III of the Constitution. Therefore, Congress may override the court on these issues:
The limitations are not based on Article III and are subject to congressional override. The court requires that the plaintiff's injury:
a) be arguably within the zone of interests protected or regulated by the statutory or constitutional provision at issue and
b) not be too generalized, that is, be particular and not shared by all or almost all citizens and
c) party is asserting her own rights, not the rights of third parties
Zone of Interest
A defendant must be arguably within the zone of interests protected or regulated by the statutory or constitutional provision at issue.
A case must not be too generalized, that is, it must be particular and not shared by all or almost all citizens.
No Third Party Standing
A defendant must be asserting his or her own rights, not the rights of third parties.
A court may reject a case if it believes that such a decision is better left to the political process or that exercising judgment would invade the powers of another branch of government. The leading case on the political question doctrine in the United States is Baker v. Carr . In Baker v. Carr, voters in TN brought suit challenging a provision enacted in 1901 that apportioned the members of the state General Assembly among the state's 95 counties. Under the 1901 standard, representation had been allocated among counties in accordance with the number of qualified voters in each county. But substantial population growth and redistribution meant that by 1961, legislative districts contained dramatically different numbers of people. The plaintiffs claimed their voting power was unconstitutionally diluted by the continued use of the 1901 apportionment. The court rejected the State's argument that the case involved a political question that should not be decided by the court. The court concluded that the cases that involve political questions have:
- Textually demonstrable constitutional commitment of the issue to a coordinate political department
- Lack of judicially discoverable and manageable standards for resolving it
- Impossibility of deciding without an initial policy determination of a kind clearly for non-judicial discretion.
- Impossibility of a court's undertaking independent resolution without expressing lack of the respect due coordinate branches of the government
- Unusual need for unquestioning adherence to a political decision already made
- Potentiality for embarrassment from multifarious pronouncements by various departments on one question
- DeFunis v. Odegaard, 416 U.S. 312 (1974)
- Roe v. Wade, 410 U.S. 113 (1973)
- Baker v. Carr, 369 U.S. 186 (1962)