Until the War on Terrorism, Vietnam was the longest conflict in American history. By the end of that war in April 1975, 57,939 would be killed or missing in action, with an estimated 250,000 South Vietnamese soldiers also dead. The Gulf of Tonkin incident sparked the great conflict that had been a series of small counterinsurgency missions. This event was the reason that President Lyndon B. Johnson justified going to Congress to appropriate military funding to expand American military involvement in Vietnam, starting a major conflict that would last until April 1975. Hosted by Colin D. Heaton. Forgotten History is a 10th Legion Pictures Production.