Each element does different work. Injury identifies a real effect on the plaintiff rather than an abstract interest shared in the same undifferentiated way by everyone. Causation connects that effect to the defendant instead of an independent third party. Redressability asks whether the requested order is likely to improve the plaintiff's position. A plaintiff can describe serious harm and still fail standing if the named defendant did not cause it or the court cannot remedy it.

Standing keeps courts focused on injuries they can remedy rather than generalized disagreement with policy. A taxpayer's objection to government spending ordinarily does not by itself create standing; nor does a prediction of harm that is merely speculative. Organizational plaintiffs may sometimes sue based on injury to the organization or on behalf of qualifying members, but advocacy alone is not an automatic ticket to court.

Different remedies can change the analysis. A past injury may support damages, while an injunction against future conduct ordinarily requires a sufficiently real threat of future harm. Being harmed once does not automatically prove that the same plaintiff faces imminent repetition. The legal merits also remain separate: a plaintiff can have standing and lose because the challenged action is lawful, or identify unlawful conduct but lack the personal stake needed to litigate it.

Worked application. A city adopts a licensing rule. A vendor denied a license alleges lost income caused by the rule and asks the court to set the denial aside. Injury, causation, and redressability are readily visible. A resident who dislikes the rule but has no business, application, or threatened enforcement presents a generalized objection rather than the same concrete stake.

Now change one fact: the vendor sues an unrelated federal agency that did not issue the license. The economic injury remains concrete, but causation and redressability weaken. This shows why standing is not a single question about whether someone was upset or harmed.

Standing is assessed when the case begins, but a dispute must remain live and must not arrive too early. That is where mootness and ripeness enter.

Video lesson: Supreme Court of the United States Procedures: Crash Course Government and Politics #20