In Vietnam, we (western Allies) helped put the French back in power after the Vietnamese had almost kicked the Japanese out
In China, we backed anti-communists (and to a less extent the communists) while we took Japan (and helped quash communist resistance to the emperor there!), its island colonies and half of Korea (where we also crushed revolution and installed a puppet government). After the war, we continued backing the anti-communists in China, and we continue backing them to this day from our island bases in Japan and Taiwan.
The Soviet Union did repeatedly request western support or alliance against fascism. The directives from Moscow—in the 20s early 30s "social democrats are the left wing of fascism"; from around 33 to Molotov-Ribbentrop "unite with the social democrats and left liberals against fascism"; from 39 to Barbarossa again "social democrats are the left wing of fascism"; and from Barbarossa to the end of the war again "unite with the liberals"—are a large part of why the cpusa took their positions.
The Soviet leadership thought these diplomatic maneuverings were necessary to preserve soviet power. I dont think they were "wrong" in the sense that "if i were in their position without the benefit of like 80 years' hindsight i'd do better." But viewed from the present with the benefit of hindsight, imo the molotovribbentrop pact and the calls to unite behind bourgeois governments were bad decisions that ultimately strengthened imperialisms chains. I think the ussr shoulda kept the "fash and socdems and liberals are all bourgeois enemies" stance throughout the whole period instead of zigzagging.
Like to start with, the Nazis were a paper tiger at first, that only grew big because people (French and Brits 1933-38, Soviets 1938-41) got scared and gave it fangs and claws. If the soviets hadnt made the pact with the nazis, they wouldnt have been able to wage their war across europe nearly as well, much less Barbarossa (Barbarossa was largely supplied by stockpiled soviet fuel). They would have sputtered out and fallen on their own, because their economy (like Italy and Japan's) were in crisis and only held together by plunder, or tried to invade with far, far less resources from no soviet trade.
It also becomes very obvious, viewing western diplomatic records, that they had no real intention of intervening unless it looked like the soviets were winning and they needed to step in to prevent the spread of communism. Thats why they kept to Africa and Italy at first, despite Stalin's repeated requests for them to open a second front against the Germans.
As Stalin stops making those requests as much or as desperately, is when they actually sent boots on the ground, bc if they didnt, the soviets would have occupied all of Germany and at minimum Greece, Italy and France would have communist revolutions. Stalin, for his part, honouring his alliance with the bourgeois states, called for the french, greek and italian communists to abandon their revolution and join with the liberal government. The greeks refused; and British soldiers shot them.
My view is that neither of these alliances (except the lendlease) benefited the USSR or the world in the long run, and they were fully unnecessary for the USSR (or other communist movements) to win the war (again, except possibly the lendlease, but even that is debated by the people that study it). The soviets would have been better served to take a strong "revolution" stance from like 1935 and support domestic armed resistance to fascism from 1939 onwards than to sell oil and other raw materials to the nazis.
But again, if I were there in Moscow in august 1939 or June 1941 or whenever with limited information idk what i'd think
Wrt CPUSA they should have at minimum absolutely opposed any annexationist goals and pushed for greater economic and military support for both the ussr and to armed resistance to fascism (and should have pushed this support to be entirely rather than only partially free), including anticolonial resistance to the vichy french government in their colonies. They should have used strikes, protests, etc, to push the USA to do more, or expose the gaps between their rhetoric of liberation and policy of domination to agitate and pull more into the movement. Instead they wholeheartedly ate up and supported the governments propaganda about the US being a force for good and actively opposed workers' job actions in favour of supporting the war effort and kickstarting the modern military industrial complex and giving the US global hegemony and a fig leaf of democracy.
The issue is that (again with hindsight), the "expand into the ussr" faction of japanese leadership had already been solidly defeated by 1939 by the "expand in China" and "expand in SEA" factions, so there was no possibility of the border skirmishes expanding to a full second front. And Japan already running into overextension problems and the limits of their production by 41. So again, while I get why the soviets made the choices they did at the time, with hindsight it seems like the wrong choice imo