Well, because CCP knew their job better than Saddam Hussein did. ;-)Yet, Iraq was invaded, not china.
China exploded its first atom bomb in 1964 and first hydrogen bomb in 1967.
Bomb matters when it's delivered. Desirably - when it can be delivered even in return.
1970s China couldn't even unleash full stockpile of warheads in first salvo, since nuclear delivery systems were limited to handful of new liquid-fueled IRBMs(in order of tens) and somewhat outdated H-6s in nuclear role. Smaller nuclear bombs, usable by tactical aircraft, as well as larger numbers of IRBMs appeared in China in 1980s.
In case of counter-force salvo - this force(already of doubtful survivability) had no proper early warning, couldn't be properly dispersed, and couldn't be kept in air(in case of bombers).
And I tell what Chinese strategic depth in these cases was called either Soviet Union(or Joseph Stalin) in early 1950s, or United States(or Jimmy Carter) in 1979 more than anything else.We are talking about China's not-so-obvious strategic depth, which provides deterrence even when they looked deceptively weak.
You just couldn't engage power of such importance and avoid involvement of the other superpower.
Again, my point: apparent disparity means nothing. It's the geopolitical and strategic depth.
Yes, and on this we can agree.
But agreement in this case means not onl what China had(and has) it, but also what Vietnam, even w/o strategic depth/reserve has actual geopolitical(geostrategic) weight, which shouldn't be forgotten.
And this is the reason, because such countries can do much more than just shake in fear.