Montana DUI Guide

DUI on Malmstrom AFB or Other Federal Property in Montana

On a military installation, a DUI can be prosecuted in federal court using Montana's own DUI statute. Base driving privileges and military discipline are handled separately.

Written by

Misty Gaubatz, Partner, A&M Law

Licensed Montana attorney and co-founder of A&M Law. Over two decades in the practice of law focusing on family law, criminal defense, and DUI defense, with federal and state court experience and a Certificate in Mediation.

Montana Bar #122346+ years as an attorney, with over two decades working in the lawReviewed by Ashley HurlbertLast reviewed: October 9, 2026

Key Takeaways: DUI on Military or Federal Property

On federal land under exclusive or concurrent federal jurisdiction, the Assimilative Crimes Act turns a violation of Montana's DUI statute into a federal offense with a like punishment (18 U.S.C. § 13).
A civilian charged this way goes to federal court, usually before a United States magistrate judge, not a Montana justice court.
A license restriction imposed by the federal court under that Act applies only within federal jurisdiction (18 U.S.C. § 13(b)(1)).
Separately, the installation can suspend base driving privileges immediately and must revoke them for at least 1 year after a refusal or an intoxicated-driving conviction (32 CFR § 634.9).
Service members are also subject to Article 113 of the Uniform Code of Military Justice, on or off base (10 U.S.C. § 913).
What kind of jurisdiction the government holds over a given piece of federal property varies, and it decides which court hears the case.

A DUI on a military base or other federal property in Montana is usually handled in federal court, but under Montana's DUI law. A federal statute called the Assimilative Crimes Act borrows the state offense and its punishment. On a military installation there are two more layers: administrative action against your base driving privileges and, for service members, military discipline. This page explains each. It is part of our Montana DUI Guide.

The Assimilative Crimes Act

Congress has not written a general federal DUI statute for military bases. Instead, 18 U.S.C. § 13(a) provides that whoever, within federal lands described in 18 U.S.C. § 7, "is guilty of any act or omission which, although not made punishable by any enactment of Congress, would be punishable if committed or omitted within the jurisdiction of the State ... in which such place is situated ... shall be guilty of a like offense and subject to a like punishment."

For a base in Montana, that means the elements and the penalty range come from MCA §§ 61-8-1002 and 61-8-1007, while the prosecutor, judge, and procedure are federal. The Act speaks to DUI directly in two ways:

What state law would impose "through judicial or administrative action" for a DUI conviction is treated as part of the punishment, but any limitation on the privilege to drive imposed under that provision "shall apply only to the special maritime and territorial jurisdiction of the United States" (18 U.S.C. § 13(b)(1)).
If a minor under 18 was in the vehicle and state law does not already add imprisonment for that circumstance, the Act adds up to 1 more year, and more if the minor is seriously injured or killed (18 U.S.C. § 13(b)(2)).

It Depends on the Kind of Federal Jurisdiction

The Act applies to land "reserved or acquired for the use of the United States, and under the exclusive or concurrent jurisdiction thereof" (18 U.S.C. § 7(3)). Not all federal property has that status. The Defense Department's traffic regulation describes the difference (32 CFR § 634.25):

Exclusive or concurrent federal jurisdiction. State traffic laws that are criminal offenses are made applicable under 18 U.S.C. § 13.
Proprietary interest only. State traffic laws cannot be enforced in federal court through the Act. Law enforcement on those installations must rely on administrative sanctions related to the installation driving privilege or on enforcement of traffic laws by state law enforcement authorities.

We have not verified the jurisdictional status of each part of Malmstrom Air Force Base, its housing areas, or the missile field sites spread across central Montana, and we will not guess. The charging document will show which court has the case. If it is a federal court, expect the District of Montana, which holds court in Great Falls among other cities (28 U.S.C. § 106).

What Federal Court Looks Like

A United States magistrate judge may try and sentence misdemeanors (18 U.S.C. § 3401). A person charged with a misdemeanor other than a petty offense may choose to be tried before a district judge instead, and the magistrate judge must explain that right. Whether a particular assimilated DUI is a petty offense depends on its maximum penalty: federal law treats an offense with a maximum of 6 months or less as a Class B misdemeanor and a maximum of more than 6 months up to 1 year as Class A (18 U.S.C. § 3559(a)). Under Montana's statute a first DUI carries a maximum of 6 months and a second or third carries a maximum of 1 year, so the classification can change with your record.

The defense issues are familiar: the basis for the stop, the field sobriety tests, and the reliability of the breath or blood result. The military regulation tells law enforcement to use standardized field sobriety tests sanctioned by NHTSA (32 CFR § 634.36), the same tests used by Montana officers. Our page on DUI defenses covers those issues.

Base Driving Privileges

Driving on an installation is a privilege the commander controls, and the administrative process does not wait for the court case. Under 32 CFR § 634.9:

Immediate suspension pending resolution is authorized after a refusal to take or complete a lawfully requested chemical test, or for operating a vehicle with a blood alcohol content of 0.08 or higher or in violation of the assimilated state law. For civilians with no Defense Department affiliation, this applies to incidents on the installation.
Mandatory revocation for not less than 1 year follows a determination that a person lawfully apprehended for DUI refused a test, or a conviction, nonjudicial punishment, or administrative action resulting in suspension or revocation of a driver's license for intoxicated driving.
A revocation "applies at all military installations, and remains in effect upon reassignment."

For a civilian employee or contractor who has to drive on base to work, this can be the most disruptive consequence.

Service Members: Article 113

A service member is subject to the Uniform Code of Military Justice wherever the conduct occurs. Article 113 covers operating or being in actual physical control of any vehicle, aircraft, or vessel while drunk, while impaired by a controlled substance, or with an alcohol concentration equal to or above the applicable limit. Inside the United States, that limit is the lesser of the state's limit and 0.08 (10 U.S.C. § 913). Punishment is "as a court-martial may direct," and commands also have administrative tools short of court-martial.

A&M Law is a Missoula firm that defends DUI cases in Western Montana. Courts-martial and military administrative proceedings are a separate system with their own defense counsel. A service member should consult military defense counsel about command action and a civilian defense lawyer about any state or federal court charge, and each lawyer should know about the other proceeding. See DUI and military service members.

Other Federal Property

Federal buildings, veterans facilities, and agency compounds each have their own rules, and the jurisdiction question above applies to all of them. National parks use a dedicated regulation instead of the Assimilative Crimes Act; see DUI in national parks and on federal land. Reservations follow a different framework again, covered in DUI on tribal reservations.

This page explains federal and Montana law in general as of October 2026. It is not legal advice about your specific case, and it is not advice about military justice proceedings.

Montana DUI Guide DUI Defense Passenger and Car Owner Liability Drinking in a Parked RV or at a Campground Sleeping in Your Car: Actual Physical Control DUI on a Horse, Bike, ATV, or Boat

FAQ

DUI on Malmstrom AFB or Other Federal Property in Montana FAQ

What happens if a civilian gets a DUI on Malmstrom Air Force Base?

Two things, on separate tracks. The criminal case can be brought in federal court under the Assimilative Crimes Act, which applies Montana's DUI statute and its punishments on federal land under exclusive or concurrent jurisdiction (18 U.S.C. § 13). And the installation commander can suspend or revoke the person's privilege to drive on base under 32 CFR § 634.9. Which court actually handles the criminal case depends on the jurisdictional status of the place where the stop happened.

Is a DUI on a military base a federal crime?

It can be. The Assimilative Crimes Act says a person who, on federal land within the special territorial jurisdiction, does something that would be punishable under the law of the surrounding state "shall be guilty of a like offense and subject to a like punishment." The Act specifically mentions convictions for operating a motor vehicle under the influence. Where the government's interest in the land is only proprietary, the Defense Department's own traffic regulation says state law cannot be enforced in federal court that way (32 CFR § 634.25(g)).

Can I refuse a breath test on base?

Under the military traffic regulation, a person who drives on the installation is deemed to have consented to tests of blood, breath, or urine when lawfully stopped, apprehended, or cited for an offense committed while driving or in physical control of a vehicle (32 CFR § 634.8(a)). A refusal triggers immediate suspension of installation driving privileges and a mandatory revocation of at least 1 year (32 CFR § 634.9).

I am active duty and got a DUI off base. Does the military get involved?

It can. Article 113 of the UCMJ covers a service member who operates or is in actual physical control of a vehicle while drunk or with an alcohol concentration at or above the applicable limit, and it is not limited to military property (10 U.S.C. § 913). Our page for military service members covers the civilian case and how it interacts with command action.

Does losing base driving privileges affect my Montana license?

They are different things. An installation revocation concerns the privilege to drive on military installations. It is not a Montana license suspension. The regulation does say that notice of a violation will be forwarded to the motor vehicle department of the host state or the person's home of record (32 CFR § 634.8(c)), so do not assume the state will never learn of it.

Stopped at the Gate or on Base?

The first step is finding out which court and which rules apply to you. Call 406-830-3060 for a confidential consultation.

Call 406-830-3060 Send a Message