I'm going to recap my points in a nutshell.
Addressing the original topic, in the world of 1972, it is impossible for China to invade Vietnam due to ideological restrictions (Vietnam being a friend and ally). Nixon did not make this deal for a reason, it cannot be done.
Agreed, but where you see ideological strictures, I see common sense. Countries don't invade their friends and allies, ideological or not.
I do not claim that China would not do it under ANY circumstances, as clearly a war broke out in 1979 when Vietnam became a military threat to China by inviting Soviet military build up in Vietnam. It's important to appreciate the change of strategic landscape in the post Vietnam War era. The war of 1979 was not aimed at overthrowing the Vietnamese government. It was a limited punitive operation similar in concept to the Sino-Indian War of 1962.
Also agreed. What I take issue with is the idea that the Chinese communists were simply too righteous to conduct cynical diplomacy like everybody else, which is based on the fact that they never did invade and overthrow a communist government. Well, obviously: they never got a reason or a chance to do so. But all the evidence (China could pursue a non-dogamtic policy, China invaded other countries, China fought other Communists, and so on) seems to suggest that the Chinese would have had no scruples.
If you want to engage in a hypothetical, like what if the Vietnamese regime collapsed in 1979 like the proverbial house of cards, would the Chinese install a friendly leadership, etc. Well that may be a practical thing to do,
Exactly. My argument is that, barring mistakes, which are of course common, everybody does what is practical or they think is practical in their diplomacy. That China (and America) warmed their relations at all seems to me clear indication that both were pragmatic in their foreign affairs.
but regime change was not the intention of the 1979 operation and therefore have no conflict on ideological ground.
I didn't say it was, I merely said that if the Chinese were so gentle with other communists, whatever happened in 1979? Your last phrase slipped me by.
For China to occupy Vietnam when it DID NOT present a threat would require a fundamental change to it's institutionalized ideological dogma.
And common sense. Nobody embarks on costly and risky operations when they don't have to. No ideology required.
The Chinese communists were reluctant to overthrow fellow communist governments because it would be blatantly imperialistic, something the Soviets don't have a problem with, but would cause all sorts of problems in China.
Such as? I've not seen any evidence besides "Well, they didn't, did they?", which as I said is not really appropriate to an alternate history site.
And in fact China has never done this. Even today they are reluctant to do a regime change in North Korea despite the fact that that government has become obnoxious to them.
And also they're showing the world a friendly face, they're part of a multilateral process and unilateral action would alienate all other parties, military operations would be costly and risky, nobody wants millions of North Korean refugees landing on them, and invading the fief of a nuclear madman is generally a stupid thing to do. Occam's razor.
My issue with your arguments is your lack of understanding that such a difference exists between the Chinese and Soviet communist world view.
There was an enormous difference, but all I did was call in Soviet anaolgies. I call in analogies which aren't carbon copies all the time.
It is a real difference that played out in how the two countries behaved in the Cold War and to some extant even today. The Chinese are loath to do military intervention when they don't have to.
As I said, everyone is loathe to do it when it's unnecessary. Nothing diplomats hate like loosing their sails to the winds of military fortune. I really don't see any reason why the Chinese are mentally incapable of installing a firendly regime.