Russia and America are colonial powers, the Soviet Union most definitely wasn’t, but they claimed the land of the previous regime including all the bits that were stolen. Colonialism in Russia wasn’t as bad as it was in the United States but it was still colonialism. Why didn’t the Soviet Union turn Siberia into one or multiple soviets like they did East Germany or Ukraine? Why did Russia get to keep it?

As for the United States I don’t see indigenous and black people being happy about the United States existing even as communist state, Mexicos claims to the south west are arguably still valid, would a communist United States return it? There’s also the glaring issue of all the islands that have active independence movements, most notably Hawaii and Purto Rico, probably wouldn’t want to associate with a communist United States even if they were independent. Is the scars of slavery, colonialism, and genocide too much for a communist United States to bare? Was colonialism in Russia small enough that a communist state could claim lands that the previous regime stolen that any actual leftist power in the United States couldn’t?

I know ideally states shouldn’t exist but certainly the path forwards would require some kind of left wing American state(s)? How much of the colonial project of the United States can be claimed by revolutionaries, it can’t be as much as Russia?