The defenses to a Montana partner or family member assault (PFMA) charge fall into three groups: the State cannot prove an element of the offense, the force you used was legally justified, or key evidence was gathered unlawfully and should be kept out. Which of them applies depends on what actually happened and what the evidence shows. This page maps each defense to the part of the statute it tests. It is the overview for the defenses section of our Montana Domestic Violence Guide.
What the State Has to Prove
Under MCA § 45-5-206(1), a person commits PFMA by doing one of three things to a partner or family member:
- purposely or knowingly causing bodily injury;
- negligently causing bodily injury with a weapon; or
- purposely or knowingly causing reasonable apprehension of bodily injury.
Each version has a relationship, a result, and a mental state. Montana law says a person is not guilty of an offense unless the person acted with the required mental state as to each element (MCA § 45-2-103(1)). The State carries the burden on all of it, beyond a reasonable doubt. You do not have to prove that you are innocent.
How Each Defense Maps to an Element
| What the State must prove | The defense that tests it |
|---|---|
| A partner or family member | The relationship is not one the statute lists |
| Bodily injury, or reasonable apprehension of it | No pain or impairment, or no fear a reasonable person would have had |
| Purposely or knowingly | It was an accident, or the mental state cannot be proved |
| That you did the act at all | The event did not happen the way it was reported |
| That the force was not justified | Self-defense, defense of another, or defense of a home or property |
A defense does not have to be exclusive. A person can say the State cannot prove bodily injury and also that any contact was accidental. What a defense cannot be is inconsistent with the evidence, which is why the first job is always to read the reports, watch the video, and listen to the 911 call.
Element Defenses: Injury, Fear, Intent, Relationship
Injury or fear. "Bodily injury" means physical pain, illness, or an impairment of physical condition, and it includes mental illness or impairment (MCA § 45-2-101(5)). It does not require a visible mark. Under the apprehension version, the fear has to be reasonable. Our page on no injury and no fear explains how those elements are contested.
Mental state. Except where a weapon is involved, PFMA requires that you acted purposely or knowingly. A true accident is not PFMA. See when it was an accident. Alcohol does not help here: read alcohol and intoxication as a defense before assuming it does.
Relationship. The statute defines "partners" and "family member" broadly, but not without limit (MCA § 45-5-206(2)). If the relationship is not one of those listed, the charge may be ordinary assault instead, which changes the consequences. See not a partner or family member.
It did not happen. Sometimes the defense is a direct denial. That is built with records, timelines, and witnesses, not with attacks on the other person. See when the accusation is untrue.
Justification Defenses
Montana calls self-defense "justifiable use of force." It is an affirmative defense (MCA § 45-3-115), which means you admit using force and say the law allowed it. Three statutes cover the situations that come up in domestic cases:
- Defense of yourself against another person's imminent use of unlawful force (MCA § 45-3-102).
- Defense of a child or another person under the same section, and a parent's reasonable and necessary force to restrain or correct a child (MCA § 45-3-107).
- Defense of an occupied structure or other property (MCA §§ 45-3-103 and 45-3-104).
The force has to be proportionate ("when and to the extent" reasonably believed necessary), and the defense is limited for a person who provoked the encounter (MCA § 45-3-105). When the defendant has offered evidence of justifiable use of force, the State has the burden of proving beyond a reasonable doubt that the actions were not justified (MCA § 46-16-131).
Evidence Defenses
Some of the most important work in a PFMA case is about what the jury will be allowed to see and hear. A motion to suppress asks the court to exclude evidence from an unlawful search or seizure (MCA § 46-13-302) or a statement that was involuntary (MCA § 46-13-301). Separately, texts, photos, and other digital evidence must be shown to be what the party offering them claims (Montana Rule of Evidence 901), and both sides can challenge a partial or edited record.
What Is Not a Defense
- Intoxication. It is not a defense and cannot be used to dispute the mental state (MCA § 45-2-203).
- The other person wants the case dropped. That is not an element. The prosecutor decides whether to go forward.
- The other person agreed to contact after a no contact order. Consent of the protected person is not a defense to violating the order (MCA § 45-5-209).
- Not knowing it was a crime. Knowledge that conduct is an offense is not an element unless the statute says so (MCA § 45-2-103(5)).
From Defense to Outcome
A defense can lead to an acquittal at trial, but it also shapes what happens before trial. A weakness in the State's proof is what a lawyer points to when asking a prosecutor to dismiss or amend a charge. Our page on whether a PFMA can be dismissed or reduced explains the routes the law provides. None of them is automatic, and no lawyer can promise one.
A&M Law is a Missoula firm that defends PFMA and other domestic violence charges in Western Montana. For how we approach these cases, see our PFMA defense page. If you or anyone in your home is in danger, call 911. The National Domestic Violence Hotline is 1-800-799-7233.
This page explains Montana law in general as of the 2025 Montana Code Annotated. It is not legal advice about your specific case.