The CIA has since its inception conducted covert actions that constitute use of military force. This paper examines the use of covert military force by the CIA in Nicaragua and the use of targeted killing by CIA drones and paramilitaries against Islamic terrorists in countries outside the declared warzones of Afghanistan and Iraq. This research utilizes a case study framework viewed from a perspective grounded from theories of just war and international law. Furthermore, this research use three theories from international relation studies to explain why the use of covert military action by the CIA is likely to continue due to the nature of international system.    International law and theories of just war explains in great detail what constitutes legitimate and illegitimate use of force, however, they do not consider the broad implications and consequences of the use of covert actions. A central component of just war is the need for states to justify their actions, which isn’t the case when they conduct their actions covertly. The material relies heavily on reports from American national security experts and historians. The results show that there are several factors within the international political system that enables the use of covert action and I put forward suggestions trying to mitigate the harm and desirability of the utilization of covert military action.