Duress in American law

Duress (a term of jurisprudence) is a possible defense, via excuse, by which a defendant may argue that they should not be held liable for actions which broke the law. 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]." A possible example of duress would involve robbing a bank in order to pay a ransom.