|This article relies largely or entirely upon a single source. (April 2008)|
|Part of the common law series|
|Other common law areas|
In jurisprudence, duress or coercion refers to a situation whereby a person performs an act as a result of violence, threat or other pressure against the person. Black's Law Dictionary (6th ed.) defines duress as "any unlawful threat or coercion used... to induce another to act [or not act] in a manner [they] otherwise would not [or would]". Duress is pressure exerted upon a person to coerce that person to perform an act that he or she ordinarily would not perform. The notion of duress must be distinguished both from undue influence in the civil law and from necessity.
Duress has two aspects. One is that it negates the person's consent to an act, such as sexual activity or the entering into a contract; or, secondly, as a possible legal defense or justification to an otherwise unlawful act. A defendant utilizing the duress defense admits to breaking the law, but claims that he/she is not liable because, even though the act broke the law, it was only performed because of extreme unlawful pressure. In criminal law, a duress defense is similar to a plea of guilty, admitting partial culpability, so that if the defense is not accepted then the criminal act is admitted.
A defendant who raises a defense of duress has actually done everything to constitute the actus reus of the crime and has the mens rea because he or she intended to do it in order to avoid some threatened or actual harm. Thus, some degree of culpability already attaches to the defendant for what was done. In criminal law, the defendant's motive for breaking the law is usually irrelevant although, if the reason for acting was a form of justification, this may reduce the sentence. The basis of the defense is that the duress actually overwhelmed the defendant's will and would also have overwhelmed the will of a person of ordinary courage (a hybrid test requiring both subjective evidence of the accused's state of mind, and an objective confirmation that the failure to resist the threats was reasonable), thus rendering the entire behavior involuntary. Thus, the liability should be reduced or discharged, making the defense one of exculpation.
The extent to which this defense should be allowed, if at all, is a matter of public policy. A state may say that no threat should force a person to deliberately break the law, particularly if this breach will cause significant loss or damage to a third person. Alternatively, a state may take the view that even though people may have ordinary levels of courage, they may nevertheless be coerced into agreeing to break the law and this human weakness should have some recognition in the law.
A variant of duress involves hostage taking, where a person is forced to commit a criminal act under the threat, say, that their family member or close associate will be immediately killed should they refuse. This has been raised in some cases of ransom where a person commits theft or embezzlement under orders from a kidnapper in order to secure their family member's life and freedom. However, duress is not a complete defense to all crimes. For example, the general rule, both at common law and today, is that duress is never a defense to murder; that is, one is never justified in killing another innocent person even if one's own life has been threatened, although this part may be questions when multiple people are threatened with death if the defendant does not kill a single or fewer people than threatened. Such a situation is similar to the ethical dilemma Trolley Problem.
For duress to qualify as a defense, four requirements must be met:
- The threat must be of serious bodily harm or death
- The threatened harm must be greater than the harm caused by the crime
- The threat must be immediate and inescapable
- The defendant must have become involved in the situation through no fault of his or her own
A person may also raise a duress defense when force or violence is used to compel him to enter into a contract, or to discharge.
In contract law
|Part of the common law series|
|Defenses against formation|
|Excuses for non-performance|
|Rights of third parties|
|Breach of contract|
|Related areas of law|
|Other common law areas|
Duress has been defined as a "threat of harm made to compel a person to do something against his or her will or judgment; esp., a wrongful threat made by one person to compel a manifestation of seeming assent by another person to a transaction without real volition". - Black's Law Dictionary (8th ed. 2004)
Duress in contract law falls into two broad categories:
- Physical duress, and
- Economic duress 
Duress to the person
Professor Ronald Griffin, Washburn University School of Law, Topeka, KS, puts physical duress simply: "Your money or your life." In Barton v Armstrong  AC 104, a decision of the Privy Council, Armstrong threatened to kill Barton if he did not sign a contract, which was set aside due to duress to the person. An innocent party wishing to set aside a contract for duress to the person need to prove only that the threat was made and that it was a reason for entry into the contract; the onus of proof then shifts to the other party to prove that the threat had no effect in causing the party to enter into the contract. Duress can be made also by social influence. Courts frown on this type of contract because there is really no manifestation of mutual assent, "meeting of the minds," or agreement to the terms. Rather, when someone is threatened and agrees to act to avoid physical harm by the party making the offer, all you truly have is a mirror of the other party's manifestation of assent not the manifestation of assent by the party being forced or induced to assent to the terms of the contract. Therefore, the meeting of the minds "in truth" does not exist. Since there is no meeting of the minds there can be no contract.
Duress to goods
In such cases, one party refuses to release the goods belonging to the other party until the other party enters into a contract with them. For example, in Hawker Pacific Pty Ltd v Helicopter Charter Pty Ltd (1991) 22 NSWLR 298, the contract was set aside after Hawker Pacific's threats to withhold the helicopter from the plaintiff unless further payments were made for repairing a botched paint job.
Economic or pecuniary duress
A contract is voidable if the innocent party can prove that it had no other practical choice (as opposed to legal choice) but to agree to the contract. 
The elements of economic duress
- Wrongful or improper threat: No precise definition of what is wrongful or improper. Examples include: morally wrong, criminal, or tortious conduct; one that is a threat to breach a contract "in bad faith" or threaten to withhold an admitted debt "in bad faith".
- No reasonable alternative (but to accept the other party's terms). If there is an available legal remedy, an available market substitute (in the form of funds, goods, or services), or any other sources of funds this element is not met.
- The threat actually induces the making of the contract. This is a subjective standard, and takes into account the victim's age, their background (especially their education), relationship of the parties, and the ability to receive advice.
- The other party caused the financial distress. The majority opinion is that the other party must have caused the distress, while the minority opinion allows them to merely take advantage of the distress. See Universe Tankships Inc of Monrovia v International Transport Workers Federation (The Universe Sentinel)  UKHL 9 
- Tiger kidnapping
- English contract law
- English criminal law
- United States contract law
- Criminal law of the United States
- Gaines, Larry; Miller, LeRoy (2006). Criminal Justice In Action: The Core. Thomson/Wadsworth. ISBN 0-495-00305-0.
- People v. Anderson, 8 Cal. 4th 767, 50 P.3d 368, 122 Cal. Rptr. 2d 587 (2002).
- See Pao On v Lau Yiu Long  3 All ER 65; Pao_On_v_Lau_Yiu_Long; Applied in Con Ange v Calogo Bloodstock AG t/as Coolmore Australia  NSWSC 666.
- "Universe Tankships Inc of Monrovia v International Transport Workers Federation (The Universe Sentinel)  UKHL 9". Bailii. Retrieved 1 August 2014.
- Westen, Peter & Mangiafico, James (2003). "The Criminal Defense of Duress: A Justification, Not an Excuse - And Why It Matters". Buffalo Criminal Law Review 6 (2): 833–950. doi:10.1525/nclr.2003.6.2.833.