Reference
Legal Rules & Concepts
In-depth explanations of 175+ foundational legal rules and concepts across constitutional law, torts, contracts, civil procedure, criminal law, evidence, and property. Each page includes key elements, landmark cases, exam tips, common mistakes, and memory aids.
Constitutional Law
Commerce Clause
Congress has the power to regulate commerce among the several states, with foreign nations, and with Indian tribes. This clause is the primary source of federal regulatory authority over economic activity.
Necessary and Proper Clause
Congress may enact laws that are necessary and proper for carrying into execution its enumerated powers and all other powers vested in the federal government. This clause expands congressional authority beyond the express text of Article I.
Supremacy Clause
The Constitution, federal laws made pursuant to it, and treaties are the supreme law of the land. State laws that conflict with valid federal law are preempted and unenforceable.
Privileges and Immunities Clause (Art IV)
States may not discriminate against citizens of other states with respect to fundamental rights and privileges, such as the right to pursue a livelihood. This clause prevents interstate protectionism against out-of-state citizens.
Privileges or Immunities Clause (14th Amendment)
No state shall abridge the privileges or immunities of citizens of the United States. Effectively gutted by the Slaughter-House Cases, this clause protects only a narrow set of rights associated with national citizenship.
Due Process Clause (Substantive)
The Due Process Clauses of the Fifth and Fourteenth Amendments protect certain fundamental rights from government interference regardless of procedures used. Fundamental rights receive strict scrutiny; other liberty interests receive rational basis review.
Due Process Clause (Procedural)
When the government deprives a person of a protected life, liberty, or property interest, it must provide adequate procedural safeguards such as notice and an opportunity to be heard. The Mathews v. Eldridge balancing test determines what process is due.
Equal Protection Clause
The Fourteenth Amendment prohibits states from denying any person equal protection of the laws. The applicable level of judicial scrutiny depends on the classification used: strict scrutiny for suspect classes, intermediate for quasi-suspect, and rational basis for all others.
Free Exercise Clause
The First Amendment prohibits government from burdening the free exercise of religion. Neutral, generally applicable laws that incidentally burden religion receive rational basis review; laws targeting religion receive strict scrutiny.
Establishment Clause
The First Amendment prohibits the government from establishing religion or favoring one religion over another. The modern test focuses on historical practices and understandings, moving away from the Lemon test framework.
Lemon Test
The three-part test from Lemon v. Kurtzman required that government action have a secular purpose, a primary effect that neither advances nor inhibits religion, and no excessive entanglement with religion. It has been superseded by the historical practices approach.
Free Speech Strict Scrutiny
Content-based restrictions on speech are presumptively unconstitutional and subject to strict scrutiny. The government must prove the restriction is narrowly tailored to serve a compelling government interest.
Time, Place, and Manner Restrictions
Content-neutral regulations of speech may be upheld if they are narrowly tailored to serve a significant government interest and leave open ample alternative channels for communication. This is the intermediate scrutiny standard for speech regulations.
Prior Restraint Doctrine
Government actions that prevent speech before it occurs carry a heavy presumption of unconstitutionality. Prior restraints, such as injunctions against publication or licensing schemes, are the most disfavored form of government restriction on expression.
Public Forum Doctrine
Government property is classified into three categories -- traditional public forums, designated public forums, and nonpublic forums -- each receiving different levels of First Amendment protection for speech activities conducted there.
Symbolic Speech Test (O'Brien)
The O'Brien test governs when the government can regulate conduct that has an expressive component. The regulation is valid if it furthers an important government interest unrelated to the suppression of expression and the incidental restriction on speech is no greater than essential.
Commercial Speech Test (Central Hudson)
Commercial speech receives intermediate protection under the Central Hudson four-part test: the speech must concern lawful activity and not be misleading, the government interest must be substantial, the regulation must directly advance that interest, and it must not be more extensive than necessary.
Takings Clause (Eminent Domain)
The Fifth Amendment prohibits the government from taking private property for public use without just compensation. This applies to physical appropriations of property by the government and requires payment of fair market value to the property owner.
Regulatory Takings (Penn Central)
Under Penn Central, a regulation that does not physically appropriate property or eliminate all economic value may still constitute a taking. Courts balance the economic impact on the owner, interference with investment-backed expectations, and the character of the government action.
Per Se Takings (Lucas)
When a regulation deprives a property owner of all economically beneficial use of the property, it constitutes a per se taking requiring just compensation, unless the restriction inheres in the background principles of the state's property or nuisance law.
State Sovereign Immunity (11th Amendment)
The Eleventh Amendment bars suits against states in federal court by their own citizens or citizens of other states. This sovereign immunity can be abrogated by Congress under Section 5 of the Fourteenth Amendment or waived by the state.
Abstention Doctrine (Pullman)
Under Pullman abstention, a federal court may abstain from deciding a constitutional question when the case presents an unsettled issue of state law that, if resolved favorably in state court, could moot or narrow the federal constitutional question.
Executive Privilege
The President has a constitutionally based privilege to withhold confidential communications from disclosure. The privilege is qualified, not absolute, and must yield when outweighed by the demonstrated specific need for evidence in a criminal proceeding.
Non-Delegation Doctrine
Congress may not delegate its legislative power to the executive branch or administrative agencies unless it provides an intelligible principle to guide the exercise of delegated authority. In practice, the Court has upheld virtually all delegations since 1935.
Separation of Powers
The Constitution divides federal power among three branches -- legislative, executive, and judicial -- to prevent tyranny and protect liberty. Each branch has distinct powers and checks on the others, and one branch may not encroach on or aggrandize power from another.
Torts
Duty of Care (General)
A defendant owes a duty of care to act as a reasonable person would to avoid foreseeable risks of harm to others. This threshold element must be established before any negligence claim can proceed.
Reasonable Person Standard
The objective standard by which a defendant's conduct is measured in negligence cases. A person must act as a reasonably prudent person would under the same or similar circumstances.
Proximate Cause (Foreseeability)
Proximate cause limits liability to consequences that are a foreseeable result of the defendant's negligent conduct. It serves as a policy-based limitation on the scope of liability beyond actual causation.
But-For Causation
The plaintiff must prove that but for the defendant's negligent conduct, the injury would not have occurred. This actual cause requirement is a necessary element of every negligence claim.
Joint and Several Liability
When two or more defendants are jointly liable, each can be held responsible for the full amount of the plaintiff's damages. The plaintiff may collect the entire judgment from any single defendant.
Comparative Negligence
A system that apportions fault between plaintiff and defendant, reducing the plaintiff's recovery by their percentage of fault rather than completely barring the claim as under contributory negligence.
Contributory Negligence
A common law defense that completely bars a plaintiff's recovery if the plaintiff's own negligence contributed in any degree to the injury. Only a handful of US jurisdictions still follow this rule.
Assumption of Risk
A defense where the plaintiff voluntarily and knowingly encountered a known risk, potentially barring or reducing recovery. It can be express (by agreement) or implied (by conduct).
Attractive Nuisance Doctrine
A landowner may owe a duty of care to trespassing children if the landowner maintains a condition on the property that is likely to attract children who cannot appreciate the danger it poses.
Negligent Infliction of Emotional Distress
A cause of action for emotional distress caused by the defendant's negligence, typically requiring physical manifestation of the distress or that the plaintiff was in the zone of danger or witnessed harm to a close relative.
Intentional Infliction of Emotional Distress
A tort claim for severe emotional distress caused by the defendant's extreme and outrageous conduct, committed intentionally or with reckless disregard. No physical contact is required.
Strict Liability (Abnormally Dangerous Activities)
A defendant who engages in abnormally dangerous activities is liable for resulting harm regardless of fault. Neither negligence nor intent must be proven — the activity itself imposes liability.
Products Liability (Strict Liability)
Manufacturers and sellers of defective products are strictly liable for injuries caused by those products, regardless of fault. The plaintiff need not prove negligence, only that the product was defective and caused harm.
Products Liability (Negligence)
A manufacturer or seller who fails to exercise reasonable care in designing, manufacturing, or warning about a product can be held liable in negligence for injuries caused by that failure.
Products Liability (Warranty)
A buyer may sue under warranty theory when a product fails to meet express or implied promises about its quality or fitness, governed primarily by the Uniform Commercial Code rather than tort law.
Vicarious Liability
An employer or principal is liable for the torts of an employee or agent committed within the scope of employment, even if the employer was not personally at fault. This is the doctrine of respondeat superior.
Premises Liability
A landowner's duty of care to persons on their property depends on the entrant's status as an invitee, licensee, or trespasser. Some jurisdictions have replaced this framework with a general duty of reasonable care.
Duty to Rescue
Under the common law, there is generally no affirmative duty to rescue a stranger in peril, even if rescue would be easy and costless. Exceptions exist for special relationships and for those who create the peril.
Good Samaritan Rule
Good Samaritan statutes protect volunteer rescuers from civil liability for ordinary negligence committed while providing emergency assistance in good faith. They do not impose a duty to act.
Economic Loss Rule
The economic loss rule bars tort recovery for purely economic losses (lost profits, diminished value) absent physical injury to person or property. Such losses must be pursued through contract or warranty law.
Loss of Consortium
A derivative claim by a spouse (and in some jurisdictions a parent or child) for the loss of companionship, affection, sexual relations, and services resulting from tortious injury to a family member.
Wrongful Death
A statutory cause of action brought by surviving family members to recover damages for losses suffered due to the decedent's death caused by another's wrongful act, neglect, or default.
Defamation (Libel and Slander)
Defamation is the publication of a false statement of fact to a third party that damages the plaintiff's reputation. Libel is written defamation; slander is spoken. Different rules apply to public and private figures.
Public Figure Doctrine (Actual Malice)
Public officials and public figures must prove actual malice — knowledge of falsity or reckless disregard for truth — to recover in defamation. This heightened standard protects First Amendment free speech values.
Invasion of Privacy
A cluster of four distinct torts protecting personal privacy: intrusion upon seclusion, public disclosure of private facts, false light, and appropriation of name or likeness.
Contracts
Consideration Doctrine
Consideration is the bargained-for exchange of legal value that makes a promise enforceable. Without it, a promise is generally a mere gift and unenforceable at law.
Promissory Estoppel
Promissory estoppel enforces a promise lacking consideration when the promisor should reasonably expect reliance, the promisee actually relies to their detriment, and injustice can only be avoided by enforcement.
Statute of Frauds
The Statute of Frauds requires certain categories of contracts to be evidenced by a writing signed by the party to be charged in order to be enforceable.
Parol Evidence Rule
The parol evidence rule bars the introduction of prior or contemporaneous agreements that contradict or supplement the terms of a fully integrated written contract.
Mailbox Rule
Under the mailbox rule, an acceptance is effective upon dispatch (when sent), while rejections and revocations are effective only upon receipt by the other party.
Mirror Image Rule
Under common law, an acceptance must exactly match the terms of the offer. Any variation in terms constitutes a counteroffer rather than an acceptance, and no contract is formed.
UCC Battle of the Forms (2-207)
UCC section 2-207 modifies the mirror image rule for goods, allowing a definite acceptance with additional or different terms to form a contract, with special rules for how those extra terms are treated.
Implied Warranty of Merchantability
Under UCC 2-314, a merchant who sells goods impliedly warrants that they are fit for their ordinary purpose, pass without objection in the trade, and conform to any promises on the label.
Implied Warranty of Fitness for Particular Purpose
Under UCC 2-315, when a seller knows of a buyer's particular purpose and the buyer relies on the seller's expertise to select suitable goods, a warranty arises that the goods will be fit for that purpose.
Perfect Tender Rule
Under UCC 2-601, if goods or their tender fail to conform to the contract in any respect, the buyer may reject the whole, accept the whole, or accept some units and reject the rest.
Substantial Performance Doctrine
Under common law, a party who substantially performs a contract in good faith, with only minor deviations, can recover on the contract minus damages for the deficiencies, rather than being treated as having breached entirely.
Anticipatory Repudiation
When a party unequivocally communicates before performance is due that they will not perform, the other party may immediately treat the contract as breached and pursue remedies without waiting for the performance date.
Impossibility of Performance
A party's contractual duty is discharged when performance becomes objectively impossible due to an unforeseen event that was not the fault of the promisor and not a risk they assumed.
Impracticability (Commercial)
Commercial impracticability excuses performance when an unforeseen supervening event makes performance extremely and unreasonably difficult or expensive, beyond the risks the promisor assumed.
Frustration of Purpose
A party's duty is discharged when an unforeseen supervening event substantially destroys the principal purpose of the contract, even though performance remains possible.
Unconscionability
A court may refuse to enforce a contract or clause that is so unfair and one-sided that it shocks the conscience, considering both procedural unfairness in the bargaining process and substantive unfairness in the terms.
Duty to Mitigate Damages
A non-breaching party has a duty to take reasonable steps to minimize the losses resulting from a breach of contract and cannot recover damages that could have been reasonably avoided.
Expectation Damages
Expectation damages are the standard remedy for breach of contract, designed to put the non-breaching party in the position they would have been in had the contract been fully performed.
Reliance Damages
Reliance damages compensate the non-breaching party for expenditures made in reasonable reliance on the contract, restoring them to the position they occupied before the contract was formed.
Restitution in Contract
Restitution requires the breaching party to return the value of any benefit conferred by the non-breaching party, preventing unjust enrichment even in the absence of an enforceable contract.
Liquidated Damages
A liquidated damages clause sets an agreed-upon amount of damages payable upon breach. It is enforceable if the amount is a reasonable forecast of harm and actual damages are difficult to estimate; otherwise, it is an unenforceable penalty.
Specific Performance
Specific performance is an equitable remedy ordering a breaching party to perform their contractual obligations, available when money damages are inadequate to compensate the non-breaching party.
Accord and Satisfaction
An accord is a new agreement to accept different performance in satisfaction of an existing obligation, and satisfaction occurs when the new performance is completed, discharging the original duty.
Novation
A novation substitutes a new party or a new contract for an existing obligation, immediately extinguishing the original duty. All parties must consent to the substitution.
Assignment and Delegation
Assignment transfers a party's contract rights to a third party, while delegation transfers contractual duties. The original party generally remains liable after delegation unless a novation occurs.
Civil Procedure
Personal Jurisdiction (Minimum Contacts)
A court may exercise personal jurisdiction over a nonresident defendant only if the defendant has sufficient minimum contacts with the forum state such that maintenance of the suit does not offend traditional notions of fair play and substantial justice.
Specific Jurisdiction
Specific jurisdiction exists when a defendant's suit-related conduct creates a substantial connection with the forum state, allowing the court to hear claims that arise out of or relate to those contacts.
General Jurisdiction
General jurisdiction allows a court to hear any claim against a defendant whose contacts with the forum are so continuous and systematic as to render the defendant essentially at home there, typically limited to domicile or place of incorporation and principal place of business.
Long-Arm Statutes
Long-arm statutes are state laws that authorize courts to exercise personal jurisdiction over out-of-state defendants, either up to the full extent permitted by due process or for specific enumerated acts performed within or affecting the state.
Subject Matter Jurisdiction
Subject matter jurisdiction is the court's authority to hear a particular type of case. Federal courts are courts of limited jurisdiction and require an independent basis such as federal question or diversity jurisdiction for every claim.
Federal Question Jurisdiction
Under 28 U.S.C. section 1331, federal district courts have original jurisdiction over all civil actions arising under the Constitution, laws, or treaties of the United States, as determined by the plaintiff's well-pleaded complaint.
Diversity Jurisdiction
Under 28 U.S.C. section 1332, federal courts have jurisdiction when the suit is between citizens of different states and the amount in controversy exceeds $75,000, requiring complete diversity among all plaintiffs and defendants.
Supplemental Jurisdiction
Under 28 U.S.C. section 1367, federal courts may exercise jurisdiction over additional claims that lack independent federal jurisdiction if they are so related to the anchor claim that they form part of the same case or controversy under Article III.
Removal Jurisdiction
Under 28 U.S.C. section 1441, a defendant may remove a civil action from state court to federal court if the federal court would have had original jurisdiction over the case, subject to procedural requirements and limitations.
Erie Doctrine
The Erie doctrine requires federal courts sitting in diversity to apply state substantive law and federal procedural law, preventing forum shopping and inequitable administration of the law between federal and state courts in the same state.
Forum Non Conveniens
Forum non conveniens is a discretionary doctrine allowing a court to dismiss a case when an adequate alternative forum exists and the balance of private and public interest factors strongly favors litigation elsewhere.
Claim Preclusion (Res Judicata)
Claim preclusion bars a party from relitigating any claim that was or could have been raised in a prior action between the same parties that ended in a valid final judgment on the merits.
Issue Preclusion (Collateral Estoppel)
Issue preclusion prevents relitigation of a specific factual or legal issue that was actually litigated, actually decided, and essential to the judgment in a prior proceeding, even in a different cause of action.
Joinder of Claims (Rule 18)
Federal Rule 18 permits a party asserting a claim to join as many additional claims as it has against the opposing party, regardless of whether the claims are related, though each claim must independently satisfy subject matter jurisdiction or qualify for supplemental jurisdiction.
Joinder of Parties (Rule 20)
Federal Rule 20 permits persons to be joined as co-plaintiffs or co-defendants if their claims or defenses arise out of the same transaction or occurrence and share at least one common question of law or fact.
Intervention (Rule 24)
Federal Rule 24 allows nonparties to join an existing lawsuit either as of right when their interests may be impaired or permissively when their claims share common questions with the pending action.
Interpleader (Rule 22)
Interpleader allows a party holding property or funds subject to multiple conflicting claims to bring all claimants into a single action, avoiding the risk of multiple liability and inconsistent obligations.
Class Action Requirements (Rule 23)
Federal Rule 23 permits representative litigation on behalf of a class when numerosity, commonality, typicality, and adequacy of representation are established, and the action fits one of three categories: prejudice, injunctive relief, or predominance of common questions.
Summary Judgment Standard (Rule 56)
Under Federal Rule 56, summary judgment is granted when the movant shows there is no genuine dispute as to any material fact and the movant is entitled to judgment as a matter of law, viewing all evidence in the light most favorable to the nonmoving party.
Motion to Dismiss (Rule 12(b)(6))
A Rule 12(b)(6) motion to dismiss tests the legal sufficiency of a complaint by arguing that, even accepting all factual allegations as true, the complaint fails to state a claim upon which relief can be granted.
Pleading Standards (Twombly and Iqbal)
Under Twombly and Iqbal, federal complaints must contain sufficient factual matter, accepted as true, to state a claim to relief that is plausible on its face, moving beyond conclusory allegations to nudge claims across the line from conceivable to plausible.
Discovery Scope (Rule 26)
Federal Rule 26 defines the scope of discovery as any nonprivileged matter relevant to any party's claim or defense and proportional to the needs of the case, requiring parties to make initial disclosures and permitting the court to limit excessive or burdensome discovery.
Work Product Doctrine
The work product doctrine protects documents and tangible things prepared in anticipation of litigation or for trial from discovery, with a qualified protection for ordinary work product and near-absolute protection for opinion work product reflecting attorney mental impressions.
Attorney-Client Privilege in Litigation
The attorney-client privilege protects confidential communications between a client and attorney made for the purpose of obtaining or providing legal advice, and it can be asserted during discovery to shield those communications from disclosure.
Sanctions (Rule 11)
Federal Rule 11 requires attorneys and unrepresented parties to certify that pleadings, motions, and other papers are not filed for an improper purpose and are supported by existing law and factual investigation, with sanctions available for violations.
Criminal Law
Mens Rea (Mental States)
Mens rea refers to the guilty mind or mental state required for criminal liability. The Model Penal Code identifies four levels: purposely, knowingly, recklessly, and negligently, each representing a decreasing degree of culpability.
Actus Reus
Actus reus is the physical or voluntary act requirement for criminal liability. A defendant must commit a voluntary bodily movement, and mere thoughts, status conditions, or involuntary acts cannot form the basis of criminal punishment.
Felony Murder Rule
The felony murder rule holds a defendant liable for murder when a death occurs during the commission of a dangerous felony, regardless of intent to kill. It eliminates the need to prove the mens rea typically required for murder.
Merger Doctrine (Criminal)
The merger doctrine prevents lesser included offenses from serving as the predicate felony for felony murder. It ensures that crimes like assault, which are inherent in every homicide, do not automatically elevate a killing to felony murder.
Conspiracy
Conspiracy is an agreement between two or more persons to commit an unlawful act, combined with the intent to achieve the criminal objective. Most modern jurisdictions also require an overt act in furtherance of the agreement.
Attempt
Criminal attempt requires the specific intent to commit a crime and a substantial step toward its commission that goes beyond mere preparation. It is an inchoate offense that allows punishment before the target crime is completed.
Solicitation
Solicitation is the crime of asking, encouraging, or requesting another person to commit a crime, with the intent that the crime be committed. The offense is complete upon the asking, regardless of whether the other person agrees.
Accomplice Liability
Accomplice liability holds a person criminally responsible for another's crime when they intentionally aid, abet, encourage, or assist in its commission. The accomplice is liable for the same crime as the principal.
Self-Defense
Self-defense justifies the use of force when a person reasonably believes it is necessary to protect themselves from an imminent unlawful attack. Deadly force is permitted only when the person faces a threat of death or serious bodily harm.
Defense of Others
Defense of others allows a person to use reasonable force to protect a third party from imminent unlawful harm. The defender may use the same level of force the third party would be entitled to use in self-defense.
Castle Doctrine
The castle doctrine eliminates the duty to retreat when a person is attacked in their own home. A homeowner may use deadly force against an intruder without first attempting to retreat, treating the home as the ultimate sanctuary.
Stand Your Ground
Stand your ground laws eliminate the duty to retreat before using deadly force in self-defense in any location where the defendant is lawfully present. Unlike the castle doctrine, they are not limited to the home.
Insanity Defense (M'Naghten)
The M'Naghten test for insanity requires the defendant to prove that, at the time of the act, a mental disease or defect caused them to either not know the nature of their act or not know that it was wrong.
Insanity Defense (Model Penal Code)
The MPC insanity test provides that a defendant is not responsible if, due to mental disease or defect, they lacked substantial capacity to appreciate the criminality of their conduct or to conform their conduct to the law.
Entrapment
Entrapment is a defense asserting that the government induced the defendant to commit a crime they were not predisposed to commit. The subjective test focuses on the defendant's predisposition, while the objective test focuses on government conduct.
Necessity Defense
The necessity defense (choice of evils) justifies criminal conduct when the defendant reasonably believed their actions were necessary to avoid a greater harm than the harm caused by the criminal act.
Duress Defense
Duress is a defense where the defendant committed a crime because of a threat of imminent death or serious bodily harm from another person. The defendant must have had no reasonable opportunity to escape the threat.
Intoxication Defense
Voluntary intoxication may negate specific intent but is no defense to general intent crimes. Involuntary intoxication is treated like insanity and can serve as a complete defense if it renders the defendant unable to understand the nature of their act.
Homicide (Degrees of Murder)
Murder is divided into degrees based on the defendant's mental state. First-degree murder requires premeditation and deliberation, while second-degree murder encompasses intentional killings without premeditation and killings committed with extreme recklessness or depraved heart.
Voluntary Manslaughter (Heat of Passion)
Voluntary manslaughter is an intentional killing committed in the heat of passion after adequate provocation. It is not a defense but a partial mitigation that reduces what would otherwise be murder to a lesser homicide offense.
Involuntary Manslaughter
Involuntary manslaughter is an unintentional killing caused by criminal negligence or during the commission of an unlawful act not amounting to a felony. It represents the least culpable form of criminal homicide.
Robbery vs Larceny vs Burglary
Larceny is the trespassory taking and carrying away of another's property with intent to permanently deprive. Robbery adds force or threat of force. Burglary is the unlawful entry into a structure with intent to commit a crime inside.
Arson
Arson at common law is the malicious burning of the dwelling house of another. Modern statutes expand it to include any structure or property and do not require the building to belong to another person.
Rape and Sexual Assault (Modern Statutes)
Modern rape and sexual assault statutes have expanded beyond common law definitions, eliminating requirements like force resistance and spousal exemption. They focus on lack of consent, broadening the range of prohibited conduct.
Double Jeopardy
The Double Jeopardy Clause of the Fifth Amendment prohibits a second prosecution for the same offense after acquittal, a second prosecution for the same offense after conviction, and multiple punishments for the same offense in a single proceeding.
Evidence
Relevance (FRE 401-403)
Evidence is relevant if it has any tendency to make a fact of consequence more or less probable. Relevant evidence is generally admissible unless its probative value is substantially outweighed by unfair prejudice or other concerns.
Character Evidence Rule (FRE 404)
Evidence of a person's character or character trait is generally not admissible to prove that on a particular occasion the person acted in conformity with that character. Exceptions exist for the accused and victims in criminal cases.
Prior Bad Acts (FRE 404b)
Evidence of other crimes, wrongs, or acts is not admissible to prove character to show action in conformity, but may be admissible for other purposes such as motive, opportunity, intent, preparation, plan, knowledge, identity, absence of mistake, or lack of accident.
Habit Evidence (FRE 406)
Evidence of a person's habit or an organization's routine practice is admissible to prove that on a particular occasion the person or organization acted in accordance with the habit or routine practice, regardless of corroboration.
Subsequent Remedial Measures (FRE 407)
When measures are taken after an injury or harm that would have made the earlier injury or harm less likely to occur, evidence of those measures is not admissible to prove negligence, culpable conduct, a defect, or a need for a warning. It may be admitted for other purposes.
Settlement Offers (FRE 408)
Evidence of settlement offers, completed compromises, and statements made during settlement negotiations is not admissible to prove or disprove the validity or amount of a disputed claim. The rule promotes candid negotiation and compromise.
Hearsay Rule and Definition (FRE 801)
Hearsay is an out-of-court statement offered to prove the truth of the matter asserted. It is generally inadmissible unless an exception or exclusion applies. FRE 801(d) defines certain statements as non-hearsay, including prior statements of witnesses and party admissions.
Present Sense Impression (FRE 803-1)
A statement describing or explaining an event or condition, made while or immediately after the declarant perceived it, is admissible as a hearsay exception. The contemporaneity requirement ensures reliability by minimizing time for fabrication.
Excited Utterance (FRE 803-2)
A statement relating to a startling event or condition, made while the declarant was still under the stress of excitement caused by the event, is admissible regardless of declarant availability. The stress of excitement is believed to override the capacity for fabrication.
Then-Existing Mental or Emotional Condition (FRE 803-3)
A statement of the declarant's then-existing state of mind, emotion, sensation, or physical condition is admissible as a hearsay exception. This includes statements of intent, plan, motive, or design, which may be used to infer subsequent conduct.
Business Records Exception (FRE 803-6)
Records of a regularly conducted business activity are admissible as a hearsay exception if made at or near the time of the event, by a person with knowledge, as part of a regular practice, and authenticated by a qualified witness or certification.
Dying Declaration (FRE 804b2)
In a homicide prosecution or any civil action, a statement made by a declarant who believes their death is imminent, concerning the cause or circumstances of their impending death, is admissible. The declarant must be unavailable.
Statement Against Interest (FRE 804b3)
A statement that was against the declarant's proprietary, pecuniary, or penal interest at the time it was made is admissible when the declarant is unavailable. The statement must be so far contrary to the declarant's interest that a reasonable person would not have made it unless true.
Former Testimony (FRE 804b1)
Testimony given at a prior proceeding or deposition is admissible when the declarant is unavailable, provided the party against whom it is offered (or a predecessor in interest) had an opportunity and similar motive to develop the testimony through examination.
Residual Exception (FRE 807)
A hearsay statement not covered by any specific exception may still be admitted if it has equivalent circumstantial guarantees of trustworthiness, is offered as evidence of a material fact, is more probative than other reasonably available evidence, and serves the interests of justice.
Confrontation Clause (Crawford Doctrine)
The Sixth Amendment Confrontation Clause bars the admission of testimonial hearsay statements against a criminal defendant unless the declarant is unavailable and the defendant had a prior opportunity to cross-examine. This constitutional rule applies independently of the hearsay exceptions.
Best Evidence Rule (FRE 1002)
To prove the content of a writing, recording, or photograph, the original is generally required. Duplicates are admissible unless a genuine question of authenticity exists or it would be unfair. Other evidence of content is admissible if the original is lost, destroyed, or unobtainable.
Authentication (FRE 901)
Before evidence can be admitted, the proponent must produce sufficient evidence to support a finding that the item is what the proponent claims it to be. FRE 901(b) provides a non-exhaustive list of authentication methods, and FRE 902 identifies self-authenticating documents.
Lay Opinion Testimony (FRE 701)
A lay witness may offer opinion testimony if it is rationally based on the witness's perception, helpful to understanding testimony or determining a fact, and not based on scientific, technical, or specialized knowledge within the scope of expert testimony.
Expert Testimony (Daubert Standard)
Under FRE 702 and the Daubert framework, expert testimony is admissible if the witness is qualified, the testimony is based on sufficient facts and reliable principles and methods, and the expert has reliably applied those methods to the facts. The trial judge serves as a gatekeeper.
Attorney-Client Privilege
The attorney-client privilege protects confidential communications between a client and their attorney made for the purpose of obtaining or providing legal advice. It is the oldest recognized privilege and belongs to the client, not the attorney.
Spousal Privilege
Two distinct spousal privileges exist: the spousal testimonial privilege (preventing one spouse from testifying against the other during marriage) and the marital communications privilege (protecting confidential communications made during marriage). They differ in who holds the privilege, duration, and scope.
Physician-Patient Privilege
The physician-patient privilege protects confidential communications between a patient and their physician made for the purpose of diagnosis or treatment. There is no federal physician-patient privilege under FRE; it exists only under state law. A related psychotherapist-patient privilege was recognized federally in Jaffee v. Redmond.
Impeachment Methods
Impeachment is the process of attacking a witness's credibility. Methods include prior inconsistent statements, bias, character for untruthfulness, specific instances of conduct, prior convictions (FRE 609), contradiction, and sensory or mental defects.
Rape Shield Rule (FRE 412)
FRE 412 generally excludes evidence of a victim's past sexual behavior or sexual predisposition in sexual misconduct cases. Limited exceptions exist in criminal cases for evidence of specific instances with the accused, third parties (to show an alternative source), or when constitutionally required.
Property
Fee Simple Absolute
The greatest estate in land recognized by law, granting the owner complete ownership rights with unlimited duration and no conditions or limitations on use or transfer.
Life Estate
An estate in land that lasts only for the duration of a designated person's life, after which the property passes to the holder of a future interest (remainder or reversion).
Fee Simple Determinable
A fee simple estate that automatically terminates and reverts to the grantor upon the occurrence of a specified event, created by durational language such as 'so long as' or 'until.'
Fee Simple Subject to Condition Subsequent
A fee simple estate that may be terminated at the grantor's election upon the occurrence of a specified condition, requiring the grantor to affirmatively exercise a right of entry to reclaim the property.
Fee Simple Subject to Executory Limitation
A fee simple estate that is automatically divested in favor of a third party (not the grantor) upon the occurrence of a specified event, creating an executory interest in the third party.
Rule Against Perpetuities
No future interest in a transferee is valid unless it must vest, if at all, no later than twenty-one years after the death of some life in being at the creation of the interest.
Doctrine of Worthier Title
When a grantor creates a future interest in the grantor's own heirs, the doctrine converts that interest into a reversion in the grantor, preventing the heirs from taking as purchasers.
Rule in Shelley's Case
When a grantor creates a life estate in a grantee and a remainder in the grantee's heirs in the same instrument, the remainder merges with the life estate to give the grantee a fee simple.
Adverse Possession
A method of acquiring title to land by occupying it continuously, openly, and without permission for a statutory period, effectively transferring ownership from the record title holder to the possessor.
Easement by Prescription
An easement acquired through continuous, open, hostile, and adverse use of another's land for the statutory period, analogous to adverse possession but granting a right of use rather than ownership.
Easement by Necessity
An easement implied by law when a parcel of land is landlocked as a result of a conveyance that severed it from access to a public road, ensuring the landlocked parcel has access.
Easement by Implication
An easement implied from the circumstances of a conveyance when a prior use of one part of the property for the benefit of another part existed before severance and is reasonably necessary to the enjoyment of the dominant parcel.
Covenant Running with the Land
A promise concerning the use of land that binds not only the original parties but also subsequent owners of the burdened property, enforceable at law through damages.
Equitable Servitude
A covenant concerning the use of land enforceable in equity by injunction against subsequent owners with notice, without requiring horizontal privity between the original parties.
Recording Acts (Race, Notice, Race-Notice)
State statutes that determine priority among competing claimants to real property by establishing rules based on the order of recording, the buyer's notice status, or both.
Bona Fide Purchaser Doctrine
A purchaser who acquires property for valuable consideration and without actual, constructive, or inquiry notice of prior adverse claims takes priority over those prior claims under applicable recording acts.
Shelter Rule
A person who acquires property from a bona fide purchaser is 'sheltered' by the BFP's protected status and takes with the same priority, even if the subsequent taker had notice or did not pay value.
Marketable Title
A title free from reasonable doubt as to its validity, free from encumbrances and defects, that a reasonable and prudent buyer would accept. Implied in every land sale contract unless disclaimed.
Warranty Deed vs Quitclaim Deed
Warranty deeds contain covenants guaranteeing the grantor's title and defending against defects, while quitclaim deeds transfer only whatever interest the grantor may have, with no warranties whatsoever.
Joint Tenancy vs Tenancy in Common
Joint tenancy features the right of survivorship (the surviving tenant automatically inherits the deceased tenant's share), while tenancy in common has no survivorship -- each tenant's share is freely devisable and inheritable.
Tenancy by the Entirety
A form of co-ownership available only to married couples, featuring the right of survivorship and protection from the individual creditors of either spouse, requiring both spouses to act jointly to transfer the property.
Landlord-Tenant Law (Types of Tenancies)
The four types of landlord-tenant estates: tenancy for years (fixed term), periodic tenancy (auto-renewing), tenancy at will (terminable at any time), and tenancy at sufferance (holdover tenant).
Implied Warranty of Habitability
A landlord's implied obligation to maintain residential rental premises in a condition fit for human habitation throughout the lease term, breach of which entitles the tenant to remedies including rent withholding or reduction.
Constructive Eviction
When a landlord's acts or omissions substantially interfere with the tenant's use and enjoyment of the premises, the tenant may treat the lease as terminated and vacate without further rent liability.
Zoning and Variances
Government regulation of land use through zoning ordinances that divide a municipality into districts with specified permitted uses, along with variance procedures allowing exceptions for unique hardship situations.