Duress consists in: (1) unlawful confinement of the person of the party, of the husband or wife of such party, or of an ancestor, descendant, or adopted child of such party, husband, or wife; (2) unlawful detention of the property of any such person; or (3) confinement of such person, lawful in form but fraudulently obtained or fraudulently made unjustly harassing or oppressive.
What Constitutes Duress
Mont. Code Ann. § 28-2-402, under Circumstances Which Affect Validity of Apparent Consent.
Mont. Code Ann. § 28-2-402