Also known as: capacities for reasoned choice · reasoned-choice capacity · mental capacity
Written by attorneys · grounded in primary & secondary sources — see below
The mental ability to understand the nature and consequences of a legal act or transaction and to act reasonably in relation to it. This capacity is assessed at the time of the act and determines whether the resulting act is legally effective.
Cecilia Cabrera, recovering from surgery and taking strong pain medication, met with a hedge fund representative and signed an irrevocable assignment transferring her entire investment portfolio. Her spouse had no independent income and pending long-term care insurance. The assignment is invalid because Cabrera lacked the mental capacity to understand its effect on her future financial security and that of her dependent spouse.
Carlos Castillo spent the afternoon drinking hard cider and smoking marijuana before a stage wedding ceremony. He laughed inappropriately, required repeated prompting to recite his lines, and showed visible disorientation during the vows. The marriage is invalid because Castillo lacked mental capacity to understand his actions and agree to them at the time of the ceremony.
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Catherine Carter, an eighty-eight-year-old assisted-living resident whose rental income supported her, hurriedly signed an irrevocable deed transferring one apartment building to a company formed by her caregiver's son. She occasionally confused relatives and properties during the meeting. The deed is likely invalid because Carter lacked the capacity to understand the gift's impact on her future financial security.
Connor Clark shot a neighbor during an argument and was later tried for murder. Evidence showed Clark had sufficient mind to comprehend the criminality and wrongfulness of the act at the time. Clark possessed the capacity for reasoned choice required for criminal liability.
Clifford Cox broke into a home while experiencing severe delusions that prevented him from appreciating the wrongfulness of his conduct. The court allowed Cox to raise an insanity defense because his mental condition eliminated the capacity for reasoned choice needed to form criminal intent.
Cassandra Cooper faced murder charges and sought to waive her right to counsel and plead guilty. The court assessed whether Cooper had the capacity for reasoned choice to understand the proceedings and make a knowing waiver. Because she possessed that capacity, the waiver was valid.
A person with mental illness incurs only voidable duties if unable to act reasonably in relation to the transaction and the other party has reason to know of the condition. Visible confusion, reliance on caregivers, and impulsive decisions below market value support avoidance when the counterparty is on notice.
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The donor must possess the mental capacity to make or revoke a will and must understand the gift's effect on the donor's future financial security and that of any dependents. Medication impairing judgment combined with dependency of a spouse supports a finding of insufficient capacity.
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Capacity is determined at the precise time of the ceremony. Visible intoxication, inappropriate laughter, and repeated prompting to recite vows establish lack of capacity to understand the actions and agree to them.
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Capacity can be partial and transaction-specific. An adult who manages simple purchases but needs daily assistance with finances and paperwork lacks capacity for a lengthy, high-risk franchise or remediation agreement.
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…S. 307 (1976); religious or political affiliation, Karcher v. Daggett , 462 U. S. 725, 748 (1983) (STEVENS, J., concurring); mental capacity, Cleburne v. Cleburne Living Center, Inc. , 473 U. S. 432 (1985); number of children, Dandridge v. Williams , 397 U. S. 471 (1970); living arrangements, Department of Agriculture v.…