Many analysts and officials have indicated that this is a critical time in the research, development, and deployment of lethal autonomous weapon systems (LAWS), both in the United States and throughout the world. As discussed below, autonomous weaponry may play an increasingly important role in Department of Defense (DOD) plans for continued U.S. asymmetric advantage in combat. Such autonomy, however, also raises numerous concerns and some vocal opposition. These concerns are of three general types: (1) the belief that risks associated with such new weapons outweigh benefits, (2) concerns about whether lethal autonomy violates the international law of war, and (3) doubts regarding the moral impropriety of machines making apparently "discretionary" decisions to take a human life. Congress has an important role to play, either as part of the public discourse regarding the future of such capabilities and appropriate policy to address them, or "behind the scenes" via its funding authority and oversight responsibilities Questions related to the research on, and development and deployment of lethal autonomous weapon systems (LAWS) have been controversial for many years. However, several factors may call for congressional attention and potential action on LAWS at this time. A nuanced understanding of LAWS and related issues may assist Congress in its role regulating the manning, funding, and equipping of U.S. military forces. LAWS are a component of the DOD's ongoing "third offset" strategy. This strategy is one way the DOD conceptualizes and integrates plans for ensuring continued asymmetric combat advantage for the United States, with particular focus on the incorporation of future technologies not easily replicated by competitor states or non-state entities. Robotics and autonomous systems have been highlighted by the DOD as a component of this overall future effort of the U.S. military. Congress also sets the legal standards for the conduct of United States forces during armed conflict through the Uniform Code of Military Justice, as well as other statutory regulation. The use of LAWS involves many moral, ethical, and strategic issues beyond considerations of military advantage. For example, as discussed below, opponents of the development of LAWS argue, variously, that such weapon systems entail unrecognized long-term risks: strategic, such as undesirable escalation or difficulty maintaining control of the technology; legal, such as the inability of LAWs to discriminate between civilian and military targets; and ethical, because they place a machine in position to make a "discretionary" decision about human lives. The DOD currently internally regulates the research, development, and deployment of autonomous weapon systems via DOD Directive (DODD) 3000.09, Autonomy in Weapon Systems (2012). In the absence of congressional or executive action, some analysts consider this DOD directive as the de facto policy of the United States on this controversial topic. Finally, Congress is an instrumental part of U.S. participation in internationally binding bodies and agreements, both via funding and treaty approval. There has been some recent consideration of LAWS at the United Nations via the Convention on Certain Conventional Weapons (CCW), the treaty that serves to restrict or ban internationally the use of certain weapons that are indiscriminant or that cause unnecessary suffering, which the United States ratified in 1995. States parties to the CCW and its various protocols agreed in 2013 to a mandate to review issues associated with LAWS, and convened meetings of experts in 2014 and 2015 to discuss these issues. Numerous international nongovernmental organizations (NGOs) view the CCW as the vehicle for advocating for multinational regulation or prohibition of LAWS. Senate approval would be required for any potential international treaty or additional protocol to the CCW, and congressional implementation may be required for any less formal agreement on the subject. A variety of options have been proposed in response to the near-term development and possible appearance of LAWS in the battlespace. The option most often discussed is the proposal to enact a complete ban on research, development, and deployment of "fully" autonomous weapon systems. Proponents argue that such bans have been effective in the past—in areas such as biological and chemical weapons they have restricted use among major nation states and thereby retarded development—and could significantly curtail development and deployment, even among nations that do not voluntarily participate in the ban. Opponents of the ban argue, in contrast, that a ban would be both undesirable and ineffective. They argue that it would be undesirable because of the substantial possibility that research in this area could eventually lead to the development of autonomous weapon systems that are more compliant with the law of armed conflict (LOAC) and other international law than current systems, as discussed below. It is also argued that such a ban would be ineffective because of two factors: (1) rapid development of civilian dual-use technologies, such as drone guidance systems and unmanned vehicles, and (2) non-U.S. peer development of these technologies. It is argued that peers will not agree to a ban, that such a ban will be unenforceable because of the ambiguity of such terms as "fully autonomous," and that such a ban, even if states publically agreed to it, would be unenforceable without a comprehensive and unlikely enforcement regime. Proponents of a ban have noted, though, that similar arguments have been raised with respect to bans on other technologies, such as blinding lasers, antipersonnel landmines, or cluster munitions, that have been negotiated and enforced. Another option for action, advocated by both proponents and opponents of a ban, is regulation of the technology—both its development and deployment. Proponents of this idea suggest that autonomous weapon development should continue, but international bodies should develop regulatory guidelines, embodied in a binding agreement like a protocol to the CCW, to describe the appropriate contours for the use of autonomous systems. In the United States, the only regulatory document currently applying to autonomous weapon systems is the Department of Defense Directive 3000.09 – lauded by some in the international community for providing a model framework for testing and basic guiding principles. Others note that regulation at the international level can be coupled with transparency, particularly regarding LOAC compliance-testing methods and systems even if the autonomous source code remains secret, to ensure that developed systems are tested as vigorously and broadly as possible, minimizing the likelihood of unexpected decisions. In sum, in the absence of a complete ban, both opponents and supporters of a complete ban on lethal autonomous weapon systems agree that LAWS should be regulated and managed. Congress would likely play a central role in any such ban or regulation of the technology, in a variety of ways. Of course, if a ban or control regime was developed via international treaty, then ratification of the treaty would require Senate approval. However, even in the absence of international action, Congress could set the legal bounds for the process of researching, developing, and deploying such systems within the DOD. Although the DOD Directive discussed above provides current standards for review and regulation of autonomous weapons, Congress could provide additional or alternate standards of review and employment. Even if Congress does not seek to supplant the specific standards developed by the DOD in its directive, there are opportunities for congressional regulation and oversight. For example, although DODD 5000.01, Defense Acquisition Systems , requires legal review of weapon acquisitions, and there are pre-existing procedures for these reviews within each of the individual services, the weapons review process may not be adequate to handle the complexity, nuance, and transparency needed for autonomous weapon review. For example, as discussed below, an understanding and review of the nature and reliability of an autonomous system's behavior is required for adequate legal analysis. However, unlike traditional weapon reviews, lawyers making judgments about autonomous systems may require technical insight or even simulation capability currently unnecessary (and therefore unavailable) when evaluating more conventionally understood effects (such as explosive radius, etc.). To meet these challenges, weapons review in this and perhaps other areas of emerging technology may benefit from more detailed standardization and centralization, or the provision of additional resources. Furthermore, the complex issues and high international profile of these weapon systems might make it appropriate to require congressional reporting and thereby oversight at intermediate stages in the acquisition and legal review process not always necessary for other weapon systems. Finally, Congress will almost certainly be presented with regulatory issues that relate to the development and employment of these technologies, but which do not directly relate to the standards of development and use within the United States. For example, Congress may be asked to consider statutory action to assist in LAWS development or prevent proliferation, perhaps by carefully regulating the export of dual use technologies in this area. Even in the absence of statutory regulatory action, congressional budgetary action on weapon system funding, as well as areas of research and development, will provide a direction for military development. There are various ways to discuss autonomy in weapon systems. The definitions of the terms, and even the taxonomy of existing systems, are not always consistent among authors on the subject. As discussed in the text box, "What is Autonomy?" the synthesized view of the many definitions acknowledges a continuum of "autonomy" in weapon systems based primarily on two factors: (1) the target specificity (the geographic, temporal, and descriptive guidance designating the target of lethal force) provided by human operators when the weapon system is set into motion, and (2) the execution flexibility (scope of potential self-initiated action) in service to assigned goals. Both the target specificity and execution flexibility of an autonomous system may vary by conflict, mission, or even individual objective. Therefore, a particular weapon system occupies a range rather than a point within the continuum of autonomy determined by its potential uses, and has a specific degree of autonomy only upon being set into motion with these parameters assigned. Discussions of the "autonomy" of a weapon system as a whole frequently refer to circumstances under which the system acts in a maximally autonomous manner.