mr. m. basset are half of the south vietnamese has disintegrated. we are in grave trouble. please plan for an evacuation and at least allow us to begin putting together lists of south vietnamese we should rescue. and he said no frank, it's not so bleak and i won't have this negative talk. young officers in the embassy began to mobilize a black operation, meaning a makeshift underground railway evacuation using outgoing cargo aircraft that would be totally below the radar of the ambassador. >> people like myself and others took the bull by the horns and organized an evacuation. in my case that meant friends of mine who were senior officers and the south vietnamese military. as the north vietnamese came closer and closer to saigon these people were dead men walking. c-span: go back to the ambassador. but part of the play in a? >> guest: graham martin was the gatekeeper and some centanni had the ability to greenlight the evacuation plan. the evacuation plan is created by the military but the ability to approve it and to put it into motion is left in the hands of the ambassador