The chapter focuses on the constitutional and legal frameworks regulating the call-out of the Australian Defence Force in aid of the civil power. This topic has become more prominent as result of the rise of global terrorism. It examines the implications of the Lindt Café siege and the 1978 Sydney Hilton bombing. The constitutional provisions of section 119 are scrutinised to determine the framework under which the military forces are deployed to assist a state against domestic violence. The Defence Act 1903 (Cth) is discussed.