In 1972, America was completing its withdrawal from the long and divisive war in Vietnam. Air power covered the departure of ground forces, and search and rescue teams from all services and Air America covered the airmen and soldiers still in the fight. Day and night these military and civilian aircrews stood alert to respond to "Mayday" calls. The rescue forces were the answer to every man's prayer, and those forces brought home airmen, sailors, marines, and soldiers downed or trapped across the breadth and depth of the entire Southeast Asia theater. Moral Imperative relies on a trove of declassified documents and unit histories to tell their tales.

Focusing on 1972, Darrel Whitcomb combines stories of soldiers cut off from their units, advisors trapped with allied forces, and airmen downed deep in enemy territory, with the narratives of the US Air Force, Army, Navy, Marines, contract pilots, and special operations teams ready to conduct rescues in Laos, Cambodia, North Vietnam, and South Vietnam. All of these missions occur against the backdrop of our withdrawal from the war and our diplomatic efforts to achieve a lasting peace. In detail, Whitcomb shows how American rescue forces supported the military response to the North Vietnamese's massive three-pronged invasion of South Vietnam, America's subsequent interdiction operations against North Vietnam, and ultimately the strategic bombing of Linebacker II.