> >There was cold war and we could have defeated the opponent.
> What does that mean in concrete terms?
A thorough de-Communistification and collective education into the principles of democratic government and statehood, like the de-Nazification of (West) Germany after WW2.
> An invasion and occupation of Russia after the fall of the USSR?
Would have been preferable, yes; mainly because it would have been required for the above. Which would have meant that under the watchful eyes of a (comparatively enlightened) occupying force, Communism would have been far less likely to be replaced by a kleptocracy -> oligarchy -> neo-Soviet pseudo-fascist rule, which is what we've seen play out in Russia over the last thirty years. (Hm, about one decade per stage of this evolution?)
> An extermination of the Russian people?
If you absolutely want to be ridiculous, go ahead and be ridiculous. Not that comments like that make anyone more negative to the idea, you know.
> What would a more complete defeat looks like?
Pretty much anything would have been preferable to what the Russian people have become: The same as they have always been, a willing herd for autocrats to rule and use.
Isn't it about time for the Russians, too, to try something other than authoritarian rule for once[1] in their thousand years of history? If they can't even catch up to the seventeenth century, what use does the world really have of a "Russian people"? The Golden Horde and the Aztecs are also gone, and nobody seems to be missing them much.
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[1]: For a bit longer than the two single decades of dithering chaos under, uhm, Kerensky? and of kleptocratic free-for-all under Yeltsin.