Also known as: mental competency · mentally competent · mental incompetency · mental capacity · competency
Written by attorneys · grounded in primary & secondary sources — see below
The mental capacity to understand the nature and consequences of a legal act or proceeding. This capacity is assessed at the time the act occurs or the proceeding takes place. Lack of such capacity renders the act voidable or subjects the proceeding to special procedural safeguards.
Melanie Morris, a plaintiff in a contract dispute, seeks to call her neighbor as a witness. The neighbor was diagnosed with schizophrenia years earlier but demonstrates during a pretrial hearing that she recalls the relevant events clearly. The court permits the testimony because the neighbor meets the threshold for competency at the time of trial.
Miguel Mendoza executes a will leaving his estate to a longtime caregiver. His children later challenge the will, presenting medical records showing progressive dementia at the time of signing. The court invalidates the will because Mendoza lacked the capacity to understand the extent of his property and the natural objects of his bounty when he signed.
Select any source to read its text and confirm it supports the definition.
Michelle Murphy and Michael Miller marry in a brief ceremony after consuming several drinks. Michelle later petitions for annulment, offering evidence that Michael was heavily intoxicated and unable to comprehend the obligations of marriage at the moment the vows were exchanged. The court grants the annulment because capacity is measured at the time of the ceremony.
Miranda Morales is charged with fraud and her attorney notices she cannot assist in preparing a defense. The prosecution moves for an examination. The court grants the motion and orders Morales evaluated under the governing statute to determine whether she can understand the proceedings and consult with counsel.
Mina Mehta, an elderly woman, transfers her primary residence to a neighbor as an irrevocable gift. Her children challenge the transfer, showing that Mehta did not appreciate how the gift would affect her own financial security. The court sets aside the gift because the donor lacked the heightened capacity required for an irrevocable donative transfer.
Marathon Logistics is a limited partnership whose operations general partner suffers a sudden neurological decline. After a court appoints a guardian, the remaining partners treat the appointment as automatic dissociation. The court later determines the dissociation occurred before winding up and holds the incapacitated partner liable for resulting damages.
No. A defendant may meet the standard for competency to stand trial yet still lack the mental competence required to conduct trial proceedings without counsel. Courts may therefore appoint counsel even when the defendant is competent to stand trial.
Supporting sources
Competence is measured at the exact time the marriage ceremony occurs. Evidence of intoxication or other impairment at that moment can render the marriage voidable even if the party appeared coherent at other times.
Supporting sources
The donor must possess the capacity needed to make a will and must also understand the gift's effect on the donor's future financial security and on anyone dependent on the donor.
Supporting sources
Yes. Federal evidence rules presume every person is competent to testify unless the rules provide otherwise. A prior diagnosis alone does not disqualify the witness if the witness demonstrates the ability to perceive, recall, and relate the events at the time of testimony.
Supporting sources
…the department and the President. Such confidences may be a ground of objection to particular questions but not to the general competency to be sworn as witnesses. Mr. Lee illustrated that if one claimed title to land under a patent from the United States and the Secretary refused a copy, a mandamus could compel production;…