Depends on how you define "America." After you change the government, economic system, culture, and name, it starts to be a Ship of Theseus thing.

The only question left is the borders, but "in a communist world" borders are less important. We might even have overlapping voting regions and sub-regions like a big complicated Venn diagram, depending on the issue at hand. Maybe everyone in the Rio Grande watershed votes on Rio Grande-related issues. If your farming community straddles the watershed divide, maybe half your neighbors vote on Rio Grande-related issues and the other half don't.

I don't see a reason to keep the current borders of America, but also, I'm not sure what the borders will even mean.