Lawful authority under Article 90 requires that the person issuing the order holds a commission as an officer and is senior to the accused either by rank or position. The officer must be in the accused’s chain of command or otherwise authorized to issue orders to the accused. This includes direct commanders, officers appointed over the accused for specific duties, and officers executing lawful orders from higher authority. The relationship can be permanent or temporary, such as an officer of the day or officer in charge of a specific operation.
The authority must be actual, not merely apparent. An officer acting outside their scope of authority or jurisdiction cannot issue orders punishable under Article 90. For example, an Army officer generally lacks authority to order Navy personnel unless in a joint command relationship. The prosecution must prove the officer’s commission, their senior position, and that they were executing official duties when issuing the order.
Courts examine whether the officer had subject matter authority over the ordered action. Medical officers can issue health-related orders, while line officers command operational matters. The key test is whether a reasonable person in the accused’s position would recognize the officer’s authority to issue that particular order. Unlawful assumption of authority or acting beyond delegated powers negates the lawful authority element, potentially reducing charges from Article 90 to Article 91 or 92.