Mont. Code Ann. § 72-7-307
Impermissible appointment
72-7-307 . Impermissible appointment. (1) Except as otherwise provided in 72-7-306 , an exercise of a power of appointment in favor of an impermissible appointee is ineffective.
(2) An exercise of a power of appointment in favor of a permissible appointee is ineffective to the extent the appointment is a fraud on the power.