Mont. Code Ann. § 45-2-202

A material element of every offense is a voluntary act, which includes an omission to perform a duty that the law imposes on the offender and that the offender is physically capable of performing, except for deliberate homicide under 45-5-102 (1)(b) for which there must be a voluntary act only as to the underlying felony. Possession is a voluntary act if the offender knowingly procured or received the thing possessed or was aware of the offender's control of the thing for a sufficient time to have been able to terminate control.