text: Chapter2
  Area denialis anaction, activity, or capability, usually short-range, designed to limit an enemy force’s
  freedom of action within an operational area (JP 3-0). Usually adversaries do not design area denial to keep
  friendly forces out, but rather to limit their freedom of action and ability to accomplish their mission within
  an operational area. Threat forces pursue AD using long-range fires, integrated air defense systems, electronic
  warfare, CBRN, manmade obstacles, and conventional ground maneuver forces. Figure 2-1 and figure 2-2
  depict employment of A2 and AD approaches in different types of theaters. For illustration purposes, A2 and
  AD reach are tied to specific capabilities. However, adversary forces can use different actions, activities, or
  capabilities in an A2 or AD approach.
  Figure 2-1. Notional U.S. European Command preclusion example