An Act relative to notice of activation of the Massachusetts National Guard within the Commonwealth

H 4664 requires the Massachusetts governor to set conditions and issue written authorization for out-of-state military units (not under federal command) to operate within the state for military duty. The governor must then provide the state legislature with written notice detailing the operation's scope, purpose, and duration. If the governor receives credible information about a federal mobilization affecting Massachusetts, they must notify the legislature within 24 hours, including specific details like scope and duration, and provide updates as needed. The bill explicitly states it does not interfere with existing interstate agreements for National Guard deployments.