Case Name -> Rule

Palsgraf v. Long Island Railroad (1982)

A defendant only owes a duty of care to plaintiffs who are within the reasonably foreseeable zone of danger.

Rylands v. Fletcher (1868)

If a defendant changes their land in a non-natural manner and harm is done to neighboring parties because of that change, the defendant is liable for those damages.

Lucy v. Zehmer (1954)

Contract formation is judged by outward expressions and conduct as a reasonable person would interpret them, not by a party’s undisclosed subjective intent.

Pierson v. Post (1805)

Ownership of a wild animal requires actual possession - either corporal seizure or mortal wounding coupled with continued pursuit - mere chase is insufficient to establish a property right.

Carlill v. Carbolic Smoke Ball Co. (1893)

While advertisements are generally considered invitations to treat rather than offers, an advertisement can constitute a valid offer if it is clear and definite in its terms, leaves nothing open for negotiation, and specifies a particular act as acceptance. Performance of that act by the offeree constitutes valid acceptance without requiring further communication.

Donoghue v. Stevenson (1932)

A person owes a duty of care to their “neighbors” - meaning persons who are so closely and directly affected by their actions that they ought reasonably to have them in contemplation when directing their conduct (Lord Atkin’s neighbor principle)

Regina v. Dudley and Stephens (1884)

Necessity is not a valid defense to murder, the law does not permit the taking of an innocent life to preserve one's own, no matter how extreme the circumstances, particularly when that innocent third party had not part in creating the dangerous situation.

Marbury v. Madison (1803)

Judicial Review - where an act of Congress conflicts with the Constitution, the Constitution is supreme and the act is void. The Constitution is the supreme law of the land, and any legislative act conflicting with it is void. It is the exclusive province of the judiciary to interpret the Constitution and strike down legislation that violates it.

Hawkins v. McGee (1929)

A valid contract requires offer, acceptance, and consideration. Where a contract is breached, the non-breaching party is entitled to expectation damages - the benefit of the bargain - meaning they should be placed in the position they would have occupied had the contract been fully performed, not merely restored to their precontract position.

Kelo v. City of New London (2005)

The government's power of eminent domain - the forced taking of private property - is satisfied by the "public use" requirement of the Fifth Amendment even when the taken property is transferred to private parties, so long as the taking is part of a comprehensive economic development plan that serves a public purpose. Courts must defer to the legislature's judgement about what constitutes a public use.