Air interdiction (AI), also known as deep air support (DAS), is the use of preventive tactical bombing and strafing by combat aircraft against enemy targets that are not an immediate threat, to delay, disrupt or hinder later enemy engagement of friendly forces. It is a core capability of virtually all military air forces, and has been conducted in conflicts since World War I. A distinction is often made between tactical and strategic air interdiction, depending on the objectives of the operation. Typical objectives in tactical interdiction are meant to affect events rapidly and locally, for example through direct destruction of forces or supplies en route to the active battle area. By contrast, strategic objectives are often broader and more long-term, with fewer direct attacks on enemy fighting capabilities, instead focusing on infrastructure, logistics and other supportive assets. The term deep air support relates to close air support and denotes the difference between their respective objectives. Close air support, as the name suggests, is directed towards targets close to friendly ground units, as closely coordinated air-strikes, in direct support of active engagement with the enemy. Deep air support or air interdiction is carried out further from the active fighting, based more on strategic planning and less directly coordinated with ground units. Despite being more strategic than close air support, air interdiction should not be confused with strategic bombing, which is unrelated to ground operations. Background In an examination of past air interdiction campaigns, Dr. Eduard Mark of the Center for Air Force History identified three methods by which an air interdiction campaign is carried out. The first is by the physical destruction or attrition of soldiers and matériel before they can reach the battlefield. The second is by severing the enemy's lines of communication, or creating blockage, to prevent soldiers and matériel from reaching the battlefield. The third is to create systemic inefficiencies in the enemy's logistic system so that soldiers and matériel arrive to the battlefield more slowly or in an uneconomical manner. While all three methods can be utilized for a tactical or strategic interdiction campaign, Dr. Mark argues their success will depend on the specific conditions at hand. Interdiction by attrition, for example, is best utilized on the tactical scale, as it is rarely possible to destroy more than a small portion of an enemy's soldiers and matériel at any one time. Destroying 100 supply trucks when an