Operation Hastings was an American military operation in the Vietnam War. The operation was a qualified success in that it pushed the People's Army of Vietnam (PAVN) forces back across the Demilitarized Zone (DMZ). As the PAVN clearly did not feel constrained by the "demilitarized" nature of the DMZ, US military leadership ordered a steady build-up of U.S. Marines near the DMZ from 1966 to 1968.