I have a good friend who was Vietnam Marine Recon. He did back to back tours 67 and 68 in Vietnam. He wanted to stay another tour but they made him go back to the US. He did for six months and then came back for a third tour. In late 80's he asked me if I wanted to go with him to Afghanistan working for the CIA supporting them fighting Russia....WTF no I'll pass. It fell through he never went.