That is a good point - perhaps there can be a pre-conflict voluntary migration, which would make the battle lines, and the resolution a lot cleaner.
The thing is, the socialists know that they can’t let the producers leave the control of their socialist utopia. If there aren’t enough in the “from those according to their means” category the “to those according to their needs” people will starve. So, the socialists will act to keep “their” means of production (people).
Odds that it is going to get ugly in the USA are the highest they have been in a long time.
Uncle Joe and the Norks weren't worried about that sort of thing; why would you think The Won's masters worry about it?