Future A2/AD challenges are part of a security environment that will be characterized by increasing complexity, uncertainty, and rapid change, according to DOD. Further, national security challenges will continue to arise from ongoing concerns such as violent extremism, the proliferation of weapons of mass destruction, resource competition, and the rise of modern competitor states, among others. These concerns, according to DOD, combined with the proliferation of advanced technologies; the increasing importance of space and cyberspace; and the ubiquity of digital networks, including social media, will make the future security environment less predictable, more complex, and potentially more dangerous than it is today. The JOAC notes that challenges to operational access are not new but that three trends promise to significantly complicate DOD’s ability to establish operational access.are According to the JOAC, the three trends Technology Improvement and Proliferation: The first important trend is the dramatic improvement and proliferation of weapons and other technologies capable of denying access or freedom of action within an operational area. Specifically, an increasing number of state and nonstate actors are developing or obtaining weapons of increasing range and accuracy. Space and Cyberspace Emergence: The second and related trend is the emergence of space and cyberspace as increasingly important and contested domains. According to the JOAC, the U.S. military will continue to derive great benefit from its space and cyberspace capabilities, but potential adversaries understand that and are increasingly targeting those capabilities. Operating in the space and cyberspace domains is also attractive to potential adversaries because actions in those domains are often difficult to attribute. Posture Changes: The third trend is that the change in U.S. overseas defense posture complicates the U.S. ability to obtain operational access. Specifically, DOD has reduced the number of overseas facilities and number of deployed forces, meaning that future operations will likely require it to deploy over longer distances. According to the JOAC, the effect of these three trends is that potential adversaries who may have once perceived that they could not stop U.S. forces from deploying into an operational area are now adopting A2/AD strategies. Figure 1 provides examples of anti-access and area denial capabilities. The JOAC describes A2/AD challenges in the context of an adversary’s strategy rather than a list of technical capabilities that need to be overcome. In general, the intent of an adversary that adopts an A2/AD strategy is to convince and, if necessary and possible, compel the United States to keep out of its affairs. At the most sophisticated level, an A2/AD strategy is not a sequential series of actions using specific military capabilities but rather an integrated and adaptive campaign using all levers of national power and influence before, during, and after any actual military conflict. Critical elements of an A2/AD strategy include keeping U.S. forces as far away as possible and imposing steeper costs on the United States than it is willing to bear. Militarily, an A2/AD environment is characterized by sophisticated adversaries using asymmetric capabilities, such as electronic and cyber warfare, space capabilities, advanced air defenses, missiles, and mines, according to DOD. The advanced weapons and technologies are characterized by their increasing precision and range, and are often affordable and increasingly proliferated. Adversaries could range from a high-end peer state that has integrated a wide range of domestically produced advanced capabilities to states, including failed or failing states, adopting a hybrid strategy that includes regular and irregular forces and a number of sophisticated weapons and technology developed at home or acquired abroad. Even nonstate actors could obtain some A2/AD capabilities, such as guided anti-ship missiles and cyber attack tools, according to DOD. Figure 2 depicts the range of A2/AD challenges. DOD has increasingly focused over the past few years on the operational access challenges it may face in the future, although it has recognized A2/AD challenges for well over a decade. For example, projecting and sustaining U.S. forces in distant A2/AD environments and defeating A2/AD threats was one of six operational goals identified in the 2001 Quadrennial Defense Review (QDR). However, DOD’s focus over the subsequent decade was on operations in Afghanistan and Iraq. As those operations began to wind down, DOD began to reemphasize the need to be able to overcome challenges to operational access. The 2012 Defense Strategic Guidance was intended to transition the department from an emphasis on current operations to preparing for future challenges, including helping guide decisions regarding the size and shape of the future force in a more fiscally constrained environment. In the guidance, the Secretary of Defense established projecting power despite A2/AD challenges as 1 of 10 primary DOD missions, noting that countries such as Iran and China will continue to pursue capabilities such as electronic and cyber warfare and ballistic and cruise missiles to counter U.S. power projection capabilities and limit the operational access of U.S. forces. Other primary missions, such as operating effectively in cyberspace and space, deterring and defeating aggression, and providing a stabilizing presence, are also relevant to overcoming A2/AD challenges. The 2014 QDR maintains the emphasis on overcoming A2/AD challenges. It builds on the 2012 Defense Strategic Guidance and continues DOD’s transition to focusing on future challenges during a time of fiscal uncertainty. The QDR states that DOD must be prepared for a full range of conflicts, including against state powers with advanced A2/AD capabilities. Further, two of the QDR’s three strategic pillars—build security globally and project power and win decisively—emphasize the importance of being able to project power and overcome challenges to access. The 2014 QDR also stresses that innovation will be paramount across all of DOD’s activities in order to best address the increasingly complex operational environment. The Chairman of the Joint Chiefs of Staff has also issued guidance in the past 2 years that emphasizes the importance of overcoming access challenges. The Capstone Concept for Joint Operations: Joint Force 2020 is the foundational concept document that describes the Chairman’s vision for how the joint force will defend the nation against a wide range of security challenges and helps establish force development priorities. Among these priorities is developing capabilities to defeat A2/AD threats, which as noted above is the specific focus of the JOAC. The JOAC includes a list of 30 required capabilities that are essential to the implementation of the concept (see app. I). It further states that this list is neither complete nor prioritized but provides a baseline for further analysis and concept development. DOD also has a number of supporting concepts to the JOAC that provide further detail on specific aspects of operations in A2/AD environments. The first of these supporting concepts is the Air-Sea Battle Concept, which is focused on overcoming the longer- range and advanced anti-access challenges. At the direction of the Secretary of Defense, the Departments of the Navy and Air Force developed this multiservice concept focused on gaining and maintaining freedom of action in the global commons, that is, the areas of air, sea, In April 2014, the space, and cyberspace that belong to no one state.Chairman of the Joint Chiefs of Staff issued the Joint Concept for Entry Operations, a supporting concept to JOAC focused on how forces will enter onto foreign territory and immediately conduct operations in the face of adversaries with increasingly effective area-denial strategies and capabilities. There are a number of other existing concepts, as well as concepts that are being developed, that support the JOAC (see fig. 3). The Army and Marine Corps are undertaking multiple efforts to address operational access challenges, which impact a broad range of their existing missions. In light of the rapidly changing operational environment, the Army and Marine Corps are reviewing how they will need to carry out their roles and functions in part by revising their service concepts and by conducting wargames that incorporate such challenges. Further, the Army and Marine Corps have identified several areas where they have important roles in overcoming access challenges, including engagement activities and entry operations, as well as logistics and missile defense for the Army. The services are beginning to take steps to change how they carry out these roles. The Army and the Marine Corps have begun examining the impact of operational access challenges on existing missions by revising their concepts and incorporating such challenges into their wargames. For example, the Army is revising the Army Operating Concept, which generally describes how an Army commander will operate in future environments that include A2/AD challenges, and identifies required capabilities in land operations. Given future operational challenges, the draft concept states that Army forces need to be agile, responsive, adaptive, and regionally engaged across the globe, and be able to conduct distributed operations. These distributed operations would involve Army elements arriving from numerous directions and domains to distributed locations in a joint operations area. According to the draft concept, this operational approach, also discussed in the JOAC, could help to overcome A2/AD challenges because the Army forces would be more spread out and thus more difficult to target and defend against. Once completed, the Army Operating Concept is to provide guidance for the Army’s development of supporting functional concepts, which eventually inform Army assessments of capability needs, gaps, and solutions. The Marine Corps has also incorporated consideration of A2/AD challenges into Expeditionary Force 21, its capstone concept, which provides guidance for how the Marine Corps will be organized, trained, and equipped to fulfill its assigned responsibilities over the next 10 years. Published in March 2014, the concept identifies the JOAC as an input and is consistent with many of its themes, including the importance of distributed operations. Expeditionary Force 21 identifies a number of challenges to Marine Corps operations caused by A2/AD threats and proposes a number of potential solutions for how the service will overcome them, including operating from amphibious ships farther from shore and using dispersed formations.