If anyone ever wanted to know the underlying reasons for the US war in Vietnam, here it is... After what they perceived as defeat of the United States in Vietnam, the editors in Business Week (April 7, 1975) feared that the Domino Theory was looming: A year later, however, US control of the Grand Area was looking much stronger:
Remember the Opium Wars where the British military kept Chinese markets open by force? I think Vietnam might have just been a continuation of that in many ways. Forcing free trade and supporting military dictatorships that will enforce property rights when it is in the interest of the business class from the country with the military power.
The threat from Vietnam was the very real internal version of the domino theory, meaning that if Washington tolerated an independant Vietnam it would embolden others to do the same and a domino would eventually make it's way to the "ultimate emerging market"- Indonesia, which is one of the reasons Washington supported General Suharto's genocide campaign and military coup in 1965. The US provided intelligence and a military assistance program to Suharto's forces. US intelligence support included a CIA supplied "death list" of suspected PKI members. As each member was executed the Army would cross out the names.
The domino theory by President Lyndon Johnson: -As under General Suharto. The domino theory by Secretary of State Dean Acheson: