April 30, 2015 marks the official end to the Vietnam War. April 1975 was as sobering month for the Washington crowd who foolishly hung on to the ideals of the Truman Doctrine. When the South Vietnamese government surrendered Saigon, it completed a remarkable run of luck for the communist rebel groups of Southeast Asia. Within a matter of a couple of weeks, the Pathet Lao, the Khmer Rouge, and the Viet Cong each took control of their respective countries as a seemingly prophetic movement which emphasized everything John Foster Dulles said during the first part of the 1950s. It was the domino theory coming to fruition: one communist country leading to another until the whole of Southeast Asia would be under communist country and the Truman Doctrine be damned!

April 30, 2015 must have been one of the bleakest days in the history of US foreign policy.

Would the communist momentum continue? What about Malaysia? Thailand? Philippines? Indonesia? Was it just a matter of time until Japan and South Korea were the last bastions of freedom in the whole Pacific Rim?

The hyperbole of opinions which undoubtedly spread quickly throughout the ranks of Washington insiders did not, perhaps, understand some of the basic elements of the communist movement of the region: everyone hated everyone else.

Yes, the Khmer Rouge in Cambodia were communist like the Viet Cong, but they hated the Vietnamese. The Vietnamese were the traditional enemies of the Chinese. There was nothing built into their comrade relationships which screamed: “We’re all going to get along and conquer the world together!” Far from it. Their screed would have been: I don’t care if you’re my communist brother, your a filthy Vietnamese! (or insert other ethnicity if spoken from a different point of view)

Within the matter of months, the Khmer started attacking Vietnamese villages, slaughtering large numbers of people. By Christmas 1978, Vietnam had had enough and launched their full-scale attack of Cambodia, driving the Khmer Rouge from power and stopping the genocidal Killing Fields in the process. In retaliation, China attacked Vietnam in the early months of 1979 to punish the Vietnamese for their invasion of Cambodia. Russia quickly aligned with Vietnam and we had all the makings of one nasty communist street fight that painfully revealed the flaws of the Domino Theory.

The Killing Fields decimated Cambodia. Vietnam stayed in Cambodia for 10 years. China and Vietnam were unfriendly for another 15 years by which time the Soviet Union had already fallen apart. Cambodia slowly emerged from its communist past. China and Vietnam abandoned their command economies and replaced it with a remarkably robust capitalistic system.

Communism stayed in power in Vietnam, Laos, and Cambodia merely as the ruling political party – not the ideological brother of Dulles’ day.

April 1975 marked the end of the domino theory, not the beginning of it. But at that time, nobody would have understood that.