During the Soviet era, South Ossetia was an autonomous oblast within the Georgian SSR. After Georgia declared independence from the USSR, South Ossetia declared independence from Georgia. They fought a war that ended in a stalemate, and Russia has essentially guaranteed South Ossetia's independence since.
Because today too, Russia claims that there is a “de facto” independent country in western Ukraine they are “helping”. Pretext for war, just as the South Ossetia pretext.
Import bit is: the West never reacted to Russian aggressions in any meaningful way.
Same how the west also didn't care, that after WW2, the USSR occupied all of Eastern Europe, or that before that, Hitler occupied Austria and Sudetenland in Czechoslovakia.
Seems like there's a historically repeating pattern here where the amount of warmongering and territorial occupation you can get away with is directly proportional to to your military force and inversely proportional to the willingness of other states to go to war with you as the occupier. Just like how the US and its coalition got away scot free after bombing the shit out of Vietnam, the middle east and destabilizing North Africa. All we could do is "condemn it" and take in refugees.
I would also add economic power and ability to inflict painful sanctions to the equation. But were you really expecting anything else? This is how it always worked and the only thing that prevents hot global scale conflicts now I think is the threat of MAD.