Police entered a home without a warrant while responding to circumstances they reasonably understood as an ongoing emergency. The Montana courts upheld the entry under an emergency-aid doctrine that Case argued demanded a more restrictive test. The Supreme Court held that Brigham City v. Stuart supplies the governing standard: officers may enter when the objective facts provide a reasonable basis to believe that someone inside is seriously injured or imminently threatened with such injury. The inquiry turns on objective reasonableness, not the officers’ subjective motives or additional state-law formulations. The entry satisfied that standard, and the judgment was affirmed.