The Montana Supreme Court has upheld the conviction of Justin Alan Boisclaire for assault and partner or family member assault. The court ruled on November 10, 2026, that Boisclaire did not demonstrate a violation of his due process rights during his trial. This decision affects Boisclaire, who was found guilty of serious charges, and sets a precedent regarding jury oath procedures in Montana.

The case, officially titled State v. J. Boisclaire, was filed under docket number DA 24-0569. It stemmed from a series of charges against Boisclaire, which included assault with a weapon and violating an order of protection. The ruling is significant as it clarifies the requirements for jury oaths and the standards for appealing convictions based on procedural issues.

In the initial proceedings, Boisclaire was charged on July 5, 2023, with assault and family member assault. The state later amended the charges to include a violation of an order of protection. During the trial, a procedural error occurred when the clerk mistakenly administered the wrong oath to the jury. Boisclaire did not object to this error at the time, which became a crucial point in the appeal.

The District Court, presided over by Judge Robert L. Deschamps III, ultimately found Boisclaire guilty on all counts. Following the verdict, Boisclaire appealed the decision, arguing that the incorrect oath compromised his right to a fair trial. He claimed that the oath did not adhere to the exact wording required by Montana law, which he believed impaired the jury's impartiality.

The Montana Supreme Court, led by Justice Laurie McKinnon, reviewed the case and concluded that Boisclaire had not met the burden of persuasion necessary for his appeal. The court noted that the oath administered to the jury, while not verbatim, still substantially complied with Montana law. Justice McKinnon stated, "the jurors swore to 'well and truly try the case and arrive at a verdict according to the evidence.'" This wording was deemed sufficient under the law.

The court also highlighted that Boisclaire's failure to object to the oath during the trial limited his ability to appeal. The court explained that, generally, failing to preserve an assertion of error waives the right to subsequent appellate review. The court stated, "The failure to preserve an assertion of error by contemporaneous objection generally waives the right to subsequent appellate review."

In its ruling, the Montana Supreme Court affirmed the lower court's decision, emphasizing that the jury was properly compiled and that the oath did not compromise the integrity of the judicial process. The court's opinion noted that the case did not present extraordinary circumstances that would warrant a review of the unpreserved objection.

This ruling has implications for future cases in Montana regarding the administration of jury oaths. It clarifies that while exact language may not always be necessary, the substance of the oath must communicate the jurors' commitment to fairly evaluate the evidence presented. The decision may influence how similar cases are handled in the future, particularly regarding procedural errors during trials.

Looking ahead, Boisclaire's options for appeal appear limited. The Montana Supreme Court's ruling is final unless new evidence or issues arise that could warrant a different legal approach. There are currently no related cases pending that could impact this ruling. The court's decision serves as a reminder of the importance of procedural adherence during trials and the challenges defendants may face when seeking to appeal based on procedural grounds.