Edit: I should probably preface this with a declaration that I haven’t slept for going on 30 hours and I haven’t ate since breakfast yesterday, so please forgive me if I’m being particularly catty. Not very scholarly or particularly gentlepersonly of me to tack this on before a gigantic screed where I am extremely catty and I’m typing this up after the fact realizing that. But you managed to get me to out of a rut and write something longer than a few sentences.

In all seriousness, we have to at least acknowledge that the ussr, under Stalin, stopped trying to expand the communist world so aggressively

You’re still hypersimplifying and outright ommitting history to the point of objective inaccuracy.

First, the USSR was not a nation but a Federation of nations. One may even call it a council union of socialist republics.

Second, the Stalin period can be generically broken up into three periods that encompass the three decades of his life spent as General Secretary - the early fifties to be excluded for the sake of simplicity with a focus on the 20s-40s - and through out each period was internationalism not abandoned.

One can try to argue that during the 20s that "internationalism was abandoned ", if ones understanding of internationalism consists of being a bone-headed war-monger with as much concrete understanding of the material conditions the Soviet - or really, any - working class faced as in the same manner of the racoon understanding the transformation that a sugar cube goes when being washed in a river, and try to paint the understanding that the failure of the ignition of a world revolution and capitalist counter-revolution wave necessitating a transformation of tactics from outright martial revolt to pursuing other more viable avenues of spreading the revolution via the Comintern to veryinf degrees of success and failure.

What of Stalins socialism in one country in the same period? Firstly, it was Lenin’s idea that was ultimately drawn in conclusion from watching the capitalists crush the attempted revolutions in the West. An idea that both the Bolshevik Left and Right agreed upon, but bickered to the point of bloodshed over on the material planning and execution of. This building of the industrial capacity of the Soviet republics occured in tandem of acts of Soviet international solidarity, be they overt acts such as the deployment of the Red Army to combat imperial Japanese incursions into Socialist Mongolia, or more covert actions such as funding and directing the communist parties of the world.

The second period of the '30s? Preparation for and defense against the inevitable invasion by the fascist armies. Fairly self-explanatory to say there are zero instances of the Soviet Union abandoning Internationalism, but a plethora of evidence contrary on the pursuit of communist internationalism and even forming the popular front against fascism.

The third period of the '40s? The hard victory over fascism. The formation of new communist nations out of the ashes of war. The formation of the COMECON and the Warsaw Treaty Organization. Arguably the greatest expansion of communist power in the world occured under Stalin in his twilight years.

and that created the space for a nation like China to develop the way that it did after events like the sino-Soviet split.

Here’s where we get closer to the crux of the issue. As seen above, an “abandonment of internationalism” was not the primary, or even tertiary cause of China going their own way - especially seeing how that same so-called abandoned internationalism supported the CPC through out its history in material means. The topic of what that support entailed or even the mistakes the comintern made in their analysis of the conditions the CPC faced in respect to their own local material conditions is a completely separate subject of discussion that deserves its own time in the sun being examined, but that’s not this post. - but the truth lies closer to the history and nature of the international aid provided to the CPC through their history of struggle. I would attribute the primary mistake that made the creation of a fractured space among the communist states known as the Sino-Soviet split was the dogmatic and paternalistic pursuit of unity under the Soviet banner. The People’s Republic of China had won their revolution, and were welcomed to the fraternity of socialist nations with open arms and material aid to help build an industrial foundation to further build upon in their own path of development. Yet, historical discontent with their party’s subordinating treatment by the comintern combined with growing diplomatic and geographic tension with the Soviets combined with their internal ideological inconsistencies that they would work upon in their own manner, would slowly boil the pot until it overflows in '61.

Of course this same problem occurred between the Soviets and Yugoslavia before that in '48. Which we could call the overture to the Sino-Soviet split. Many of the - simplified - same reasons strike here as well. But that’s also another topic for another post.

Finally

“Stalin decided it was better to build the Union up and pay out at least some peace dividend than to keep up the hellish war economy against the west.”

The great patriotic war was a purely defensive war against fascist invaders that bled the Soviet peoples dry. Do you know what happened in the period between the victory that was won in the west and the redeployment of the Red Army to liberate occupied North-East China and the Korean peninsula? Stalin ordered the demobilization of construction workers, teachers, doctors, and other groups necessary to begin rebuilding the ruined western part of the motherland. There was zero desire to go anywhere beyond ending the fascist threat and going home. There was zero desire to begin senselessly killing the allies the Soviet people fought with and on the behalf for for half a decade. There was zero desire to gun down the friends the soldiers of the Red Army made on Elbe day. Thinking doing anything other than ending the war and sending the brave Soviet men and women home screams deeply unserious “redditor” to me.