Mistake of act is another basis for setting aside a will, in whole or in part. Mistake is a state of mind of the testator who holds a belief not in accord with the facts. Mistake may result from inadvertence or intellectual lack or from the testator’s innocent or negligent conduct or misrepresentation by a beneficiary or third person, including an attorney. Fraud is an extreme type of mistake resulting from culpable, as opposed to innocent or negligent, conduct or from misrepresentation and will be treated separately. Negligent mistake occurs most often when counsel fails to draft a will or a provision in a will in accord with the testator’s instructions or intentions.
Nonfraudulent mistake is not the same as lack of testamentary capacity, although both are a mental condition. Unlike testamentary capacity, mistake is an affirmative belief and not passive ignorance. The testator’s mistaken belief actively induces the testamentary disposition under attack and may relate to many kinds of fact. For example, the testator may:
The testator maybe the victim of mistake so fundamental that it defeats testamentary intent and avoids the document as a whole. A mistake as to the nature of identity of the whole document usually is a basis to deny probate completely.
The testator, understanding that he/she is executing a will, may also be mistaken as to the whole contents, or as to only part of the contents. This may be due to negligence of counsel who fails to carry out the testator’s instructions. Partial mistake, such as the omission of an intended gift or the conferring of an unintended gift or misdescriptions of persons or property, are usually treated as not being so fundamental as to avoid probate.
Sometimes, the contestant seeks avoidance of the will on the ground of a mistake of law, alleging the testator was mistaken as to the legal consequences of an assumed set of facts. Most Courts will not set aside a will on this ground in the absence of a total failure of testamentary intent.