The Montana Supreme Court delivered its opinion Monday in *Cooper v. Montana Department of Justice*, a case examining whether state authorities can require sex offender registration based on out-of-state convictions. Justice Laurie McKinnon delivered the court's opinion in the matter, which was decided Jan. 13, 2026.
Wesley Thomas Cooper appealed a May 21, 2025 order from the District Court of the Nineteenth Judicial District in Lincoln County that denied his writ of prohibition against the Montana Department of Justice. The district court's order required Cooper to register in Montana as a sex offender based on his conviction for sexual assault in North Dakota.
The case originated when Cooper challenged Montana's authority to compel his registration as a sex offender based on his North Dakota conviction. Cooper sought relief through a petition for a writ of prohibition, arguing that the state lacked jurisdiction to impose registration requirements based on his out-of-state offense.
The Montana Supreme Court addressed three key legal questions in the appeal. First, whether the district court erred in concluding that the proper avenue of relief from sex offender registration duties was a petition for removal under Montana Code Annotated § 46-23-506, rather than Cooper's chosen writ of prohibition. Second, whether the district court improperly relied on unproven allegations when determining Cooper's registration obligations. Third, whether North Dakota's sexual assault statute is reasonably equivalent to Montana's sexual offense provisions that trigger registration requirements.
Sex offender registration laws create complex jurisdictional issues when individuals move between states or have convictions in multiple jurisdictions. Montana, like other states, maintains a sex offender registry that requires individuals convicted of certain sexual offenses to register their personal information and location with law enforcement authorities. These registries serve public safety purposes by tracking the whereabouts of individuals deemed to pose ongoing risks.
The interstate application of sex offender registration requirements often depends on whether out-of-state convictions are deemed "reasonably equivalent" to in-state offenses that trigger registration obligations. This legal standard requires courts to compare the elements and scope of different states' criminal statutes to determine whether they cover substantially similar conduct.
Cooper's case highlights the procedural complexities that arise when individuals challenge registration requirements. The question of whether to pursue relief through a writ of prohibition versus a petition for removal under state statute reflects broader issues about the appropriate legal mechanisms for contesting sex offender registration obligations.
A writ of prohibition is an extraordinary legal remedy that seeks to prevent a government entity from taking action beyond its lawful authority. Cooper's choice of this procedural vehicle suggests he believed Montana lacked jurisdiction to impose registration requirements based on his North Dakota conviction. The state's position, upheld by the district court, was that Cooper should have pursued the statutory removal process instead.
The case also raises questions about the evidentiary standards courts must apply when determining registration obligations. Cooper argued that the district court improperly considered allegations that were not proven beyond a reasonable doubt or admitted by him as a defendant. This issue touches on fundamental due process concerns about the burden of proof required when imposing ongoing civil obligations based on criminal conduct.
Interestate sex offender registration has become increasingly complex as states have expanded their registry requirements and enhanced information sharing between jurisdictions. Federal legislation, including the Adam Walsh Child Protection and Safety Act, has encouraged states to adopt more uniform approaches to sex offender registration and notification.
The comparison between North Dakota's sexual assault statute and Montana's corresponding provisions requires detailed legal analysis of the specific elements and penalties associated with each state's criminal code. Courts must examine not only the statutory language but also how the laws are interpreted and applied in practice.
Cooper was represented by Colin M. Stephens of Stephens Brooke, P.C. in Missoula. The state was represented by Montana Attorney General Austin Knudsen and Assistant Attorney General Caitlin S. Williams. The case was submitted on briefs Oct. 29, 2025, without oral arguments.
The decision will likely have implications for other individuals facing similar interstate registration requirements and could influence how Montana courts handle future challenges to sex offender registration obligations. The ruling may also affect the procedures that individuals must follow when seeking relief from registration requirements.
Sex offender registration laws continue to evolve as states balance public safety concerns with constitutional protections for individuals with criminal convictions. The Montana Supreme Court's decision in *Cooper* adds to the growing body of case law addressing the scope and application of these registration requirements across state lines.
The full implications of the court's ruling will depend on the specific reasoning and holdings contained in Justice McKinnon's complete opinion, which addresses the procedural and substantive legal questions raised by Cooper's challenge to Montana's registration requirements.