AirLand Battle doctrine, driven by rigorous training, an all-volunteer force and an effectively integrated joint team, produced a string of successes in conventional warfare against symmetrically equipped forces. In these operations, tactical aviation, including close air support and attack helicopters, proved decisive when combined with landpower. Some symmetrical threats remain, but increasingly, opponents are seeking asymmetrical advantages, ranging from nuclear capability to irregular warfare. As a result, U.S. forces must be capable of responding anywhere along the spectrum of conflict from high-intensity conventional warfare to stability support operations. The most likely threats over the near and mid terms are irregular forces operating predominantly on the ground in complex urban environments, with the potential of being equipped with weapons of mass destruction.1 Therefore, across the range of possible contingencies the United States must establish an overarching security environment to successfully employ all elements of national power.