Convinced that the collapse of South Vietnam would result in the whole of South-East Asia being overrun by the Communists, America became deeply involved in the struggle. Its troops joined in the fighting, and its aircraft bombed suspected Vietcong bases and supply lines. South Vietnam was also helped by military units from South Korea, Australia, New Zealand, the Philippines and Thailand.

At first, the Americans confined their air attacks to the South, but following an incident in August 1964, in which two US destroyers had been supposedly fired on by North Vietnamese patrol boats within the Gulf of Tonkin, they also began bombing military installations within the North. The weekly bomb tonnage dropped on North Vietnam soon exceeded the bombs dropped on Germany throughout the height of World War II.

Paddy fields and forests had been also sprayed with poisonous defoliant or seared with napalm – fireballs of petroleum jelly – to deny the Vietcong food and cover. ‘We have the power,’ declared US Defence Secretary Robert McNamara, ‘to knock any society out from the 20th century.’

Even so, victory in Vietnam continued to elude the Americans. In February 1968, during the lunar New Year festival of Tet, the Vietcong launched a devastating offensive of their own. They attacked over 100 targets in the South, even fighting their way into the grounds of the US Embassy compound within the capital, Saigon.

It was not only on the military front that America was suffering setbacks. Vietnam was the first war to receive extensive coverage on television, and viewers throughout the globe had been shocked by pictures of the richest nation on earth unleashing its military might against one from the poorest.