3-76. The JFC is the designated engagement authority in theater, though engagement authorization is typically delegated to a subordinate commander. The subordinate commander, the area air defense commander, may in turn further delegate the authority to execute engagements; further delegation is based on mission, enemy, terrain and weather, troops and support available, time available, and civil considerations. The kill chain is the successive linkages of commanders who can authorize engagements of air and missile threats. The kill chain begins with a joint authority, such as the area air defense commander, and may include ADA commanders down to battery level. The kill chain is involved in all engagement decisions whether centralized or decentralized.