Senior military officials recently testified before Congress that current and future adversaries are likely to use "hybrid warfare" tactics, a blending of conventional and irregular approaches across the full spectrum of conflict. In addition, several academic and professional trade publications have commented that future conflict will likely be characterized by a fusion of different forms of warfare rather than a singular approach. The overarching implication of hybrid warfare is that U.S. forces must become more adaptable and flexible in order to defeat adversaries that employ an array of lethal technologies to protracted, population-centric conflicts such as those in Iraq and Afghanistan. Department of Defense (DOD) officials have discussed the need to counter the continuum of threats that U.S. forces could face from nonstate- and state-sponsored adversaries, including computer network and satellite attacks; portable surface-to-air missiles; improvised explosive devices; information and media manipulation; and chemical, biological, radiological, nuclear, and highyield explosive devices. In light of references to "hybrid warfare" by senior military officials and possible implications it could have for DOD's strategic planning, Congress requested we examine: (1) whether DOD has defined hybrid warfare and how hybrid warfare differs from other types of warfare and (2) the extent to which DOD is considering the implications of hybrid warfare in its overarching strategic planning documents. On June 16, 2010, we met with congressional staff to discuss the preliminary results of our work. This report formally transmits our final response to Congress' request.
Senior military officials in recent public testimony asserted the increased likelihood of U.S. forces encountering an adversary that uses hybrid warfare tactics, techniques, and procedures. However, DOD has not officially defined hybrid warfare at this time and has no plans to do so because DOD does not consider it a new form of warfare. Rather, officials from OSD, the Joint Staff, the four military services, and U.S. Joint Forces Command told us that their use of the term hybrid warfare describes the increasing complexity of future conflicts as well as the nature of the threat. Moreover, the DOD organizations we met with differed on their descriptions of hybrid warfare. For example, according to Air Force officials, hybrid warfare is a potent, complex variation of irregular warfare. U.S. Special Operations Command officials, though, do not use the term hybrid warfare, stating that current doctrine on traditional and irregular warfare is sufficient to describe the current and future operational environment. Although hybrid warfare is not an official term, we found references to "hybrid" and hybrid-related concepts in some DOD strategic planning documents; however, "hybrid warfare" has not been incorporated into DOD doctrine. For example, according to OSD officials, hybrid was used in the 2010 Quadrennial Defense Review Report to draw attention to the increasing complexity of future conflicts and the need for adaptable, resilient U.S. forces, and not to introduce a new form of warfare. The military services and U.S. Joint Forces Command also use the term "hybrid" in some of their strategic planning documents to articulate how each is addressing current and future threats, such as the cyber threat; however, the term full spectrum often is used in addition to or in lieu of hybrid.