Are we talking a democratic ex-USSR here? Because the USSR's constitution, pretty much from the beginning, established a right to secession for the republics. Sure, this was solely theoretical up till 1989 or so, but once the USSR starts democratizing and actually following its own constitution-well, that constitution says any full member of the union has the right to go anytime they want to. So either the Soviet Union has got to respect this, or violate its own constitution in a really major way, which would set a rather damaging precident really early in the democratic transition.
Perhaps we could have a POD in the 1920's that results in the Soviet Union adopting a more centralized structure, like the Tsarist system it replaced, or even adopting a federal structure but denying the republics a right to secession (maybe something about the republics being in a "perpetual union of the working classes" or something like that). Since pretty much all meaningful Soviet politics went on within the Communist Party anyway, its hard to see how this would matter all that much, and one could imagine Soviet history going more or less the same as OTL up till 1989-but then, once the Communist Party goes away and the Union is forced to actually start using its formal constitution, there isn't an automatic escape hatch for anyone who wants to leave.
The U.S.S.R's constitution was altered umpteen times over the dcades it could change again. Indeed it would have to for any democratic regime to emerge...
Granted. It would be a clusterfuck though.
Just because Putin's Russia is Shangri-La in comparison with Stalin's it doesn't make it fairly democratic. It's not North Korea or Syria but it's objectively an authoritarian regime as both the Democracy Index and the Freedom House see it.
Authoritarian democracy perhaps but not a dictatorship, Democracy Index and the Freedom House are not unbiaised sources.
Armenia and Azerbaijan were not guaranteed to leave, the only one that was really irreconcilable was Georgia. The Soviets would have to pay in blood to keep it, and it would make Chechnya look like a cakewalk. Inevitably they would also have to do it, there cannot be an independent Georgia along with a Soviet Armenia and Azerbaijan, it's geographically impossible, the Red Army is going to have to go in.
Um, no just no, middle class Georgians arnt going to go all death-commando the way the Chechens did.
If anything any bloodshed in Georgia would be betten the ethnic groups who live there not partisan's & terrorists v fedral troops & police.