US Army/1st Lt. Ryan DeBooy During the Vietnam War, US commandos developed an insertion and extraction method that is still used today. Now, with conflict in Southeast or East Asia a growing prospect, its an increasingly relevant but still risky method. During the Vietnam War, American commandos developed an insertion and extraction method for operations in the jungle that is still used by today's special operators. The Special Patrol Insertion/Extraction (SPIE) system is designed for small special-operations teams that operate in areas where an enemy presence or the terrain prevents helicopters from landing. The SPIE technique hasn't been used operationally for decades, in part because US air superiority and lackluster enemy anti-aircraft capabilities have meant it wasn't needed.