If officers come to your home after you have driven there, they generally cannot come inside to arrest you for a misdemeanor DUI without a warrant, consent, or a true emergency. The Montana Supreme Court has suppressed evidence in exactly that situation. That does not make the case go away: officers can investigate from the doorstep, seek a warrant, and build a case from witnesses. This page explains where the lines are. It is part of our Montana DUI Guide.
The Home Is Protected Differently
Article II, Section 11 of the Montana Constitution secures people in their homes against unreasonable searches and seizures, and Section 10 adds an express right of privacy. In State v. Saale, 2009 MT 95, 350 Mont. 64, the Court restated the rule: warrantless searches and seizures conducted inside a home are per se unreasonable, subject to a few carefully drawn exceptions. Exigent circumstances are one exception, and the State bears a heavy burden to show them.
State v. Saale: A Missoula County Example
A driver rolled her vehicle near Clinton shortly after leaving a bar. Witnesses helped her out and thought she was highly intoxicated but not seriously hurt. Her husband arrived and drove her home before officers got there. Troopers went to the house. The husband refused to let them in or to bring her out. After a call to the on-call prosecutor, the troopers handcuffed the husband, went inside, took the driver back to the crash scene, and arrested her for DUI.
The State offered two emergencies. The Supreme Court rejected both.
- Disappearing evidence. The State argued her blood alcohol level would be lost. The Court answered that a person's alcohol concentration is not physical evidence until a sample exists, so there was nothing yet to destroy. It also noted that after taking her from the house, officers left her in a patrol car for 45 minutes before giving a roadside breath test.
- Possible injury. Witnesses had already told officers she did not appear seriously hurt, her husband was with her, and the officers did not take her to an emergency room.
The Court concluded the State had not shown truly exigent circumstances and reversed the denial of the motion to suppress.
The Nighttime Arrest Statute
Montana also has a statute on point. An arrest may be made at any time of the day or night, "except that a person may not be arrested in the person's home or private dwelling place at night for a misdemeanor committed at some other time and place unless upon the direction of a judge endorsed upon an arrest warrant" (MCA § 46-6-105). The statute carves out arrests for partner or family member assault. The section does not define "night."
In City of Billings v. Whalen, 242 Mont. 293 (1990), an officer saw a driver cut a corner at about 10:15 p.m., followed him two blocks home without lights or siren, and stopped him as he was straddling the threshold of his front door. Field sobriety tests and a DUI charge followed. The Supreme Court affirmed suppression of all the evidence: the driver was arrested in his home, at night, without a warrant, for a misdemeanor committed elsewhere. In Saale the Court said it would normally rely on this statute as well, but the argument had not been raised in the trial court.
A first, second, or third DUI is a misdemeanor, so the statute matters in most DUI cases.
What Officers Can Still Do
- Knock and ask. Nothing in these cases stops an officer from coming to the door and asking questions, or from talking with you if you choose to step outside. The protection the cases describe begins at the entrance to the home.
- Ask to come in. Consent is an exception to the warrant requirement. In Saale, the husband's refusal is the reason there was no consent.
- Get a warrant. A judge may issue a search warrant on a sworn application showing probable cause, and a warrant may reach blood samples (MCA §§ 46-5-221, 46-5-224). See blood draw warrants.
- Request a test. The implied consent law lists a crash with property damage, and a crash with serious bodily injury or death, among the situations in which a test must be administered at an officer's direction when the officer has probable cause (MCA § 61-8-1016(2)(a)(iii)).
Proving Who Drove, and When
A roadside arrest answers two questions at once: who was driving, and what condition they were in at the time. A contact at home answers neither directly. The State has to prove that you drove, or were in actual physical control, while under the influence or over a limit (MCA § 61-8-1002(1)).
Three things usually decide these cases:
- Identity. Did anyone see who was behind the wheel? A report of a vehicle and a plate identifies a car, not a driver. See anonymous tips and reported drivers.
- Timing. The statutory inferences from an alcohol test apply to a sample taken "within a reasonable time after the alleged act" (MCA § 61-8-1002(2)). The longer the gap, and the less certain the time of driving, the harder it is to connect a number to the drive.
- Drinking after driving. If a person drank after getting home, a later test measures that too. Whether that account holds up depends on the evidence.
Your own words are often the State's best evidence on all three. In Saale, the driver told the trooper she had been driving, though in that case the statement came after the unlawful entry. Statements made voluntarily at the door, before any arrest, are generally usable.
If There Was a Crash
Leaving the scene raises a second set of problems, because Montana imposes duties on a driver that are separate from DUI.
| If you hit | The duty | MCA |
|---|---|---|
| A crash with another person | Stop immediately and remain at the scene until you have given your name, address and registration number, shown your license on request, and given reasonable help to anyone injured. | MCA §§ 61-7-103, 61-7-105 |
| An unattended vehicle | Stop, and either find the owner or leave a written note with your name and address and what happened. | MCA § 61-7-106 |
| A fence, sign or other property | Take reasonable steps to find and notify the owner. | MCA § 61-7-107 |
| Injury, death, or apparent damage of $1,000 or more | Give immediate notice to the police, sheriff or highway patrol by the quickest means of communication. | MCA § 61-7-108 |
A driver who went home after a collision may face a leaving-the-scene charge whether or not a DUI can be proved. How a crash changes a DUI charge itself is covered in DUI with a crash or a child in the car.
If It Already Happened
Write down the sequence while you remember it: when you got home, who was there, when officers arrived, what was said at the door, whether anyone came inside and how, and what time any test was given. Those details are what a motion to suppress is built from (MCA § 46-13-302), and they bear on whether the State can tie a test result to the drive at all.
This page explains Montana law in general as of the 2025 Montana Code Annotated and the court decisions cited. It is not legal advice about your specific case.