The issue that concerned planners from the 1950s was the usual one: independent nationalism in Vietnam might prove successful in terms meaningful to others in the region facing similar problems, and the “virus” might spread, “infecting” others, in Thailand, Malaya, sooner or later Indonesia, which was regarded as the second-most important domino.
The most important domino (the “superdomino,” as Asia historian John Dower described it) was Japan, which might decide to “accommodate” to a more or less independent South East Asia, perhaps linked at least loosely to China, becoming the industrial, technological, and commercial center of a “New Order in Asia,” independent of the US. That would have meant that the US would have effectively lost World War II in the Pacific, which was fought in large part to block that outcome.
That intolerable consequence was prevented, very efficiently, by the rational means of destroying the virus of potential successful economic development in Vietnam, and “inoculating” the region, often by the support of brutal and vicious military dictatorships, including Indonesia, after the failure of Eisenhower’s efforts to break off the outer islands (where most of the wealth is) in 1958. That’s a very considerable victory, and the US corporate system has gained enormously from it — which, incidentally, includes China.
…[Quite] a different matter: that US control is not complete, which is certainly true. That’s the case with every system of dominance and control. And the US victory in Vietnam (solidified later, as Vietnam succumbed to the neoliberal order) is quite a separate matter from the place of China in the world system now developing. If anything, the US victory in Vietnam imposed constraints on China’s potential power.