The way it works now, is that if any of the Baltics (or Finland) go red, they vote to join the USSR, either by puppet or by annexation, which the USSR can either approve of or reject. Other than that, a decision to surrender pops up as they're justifying a wargoal.I believe there's already a 'invade the baltics' focus for the soviet tree- perhaps a minor rework to it where it also unlocks decisions to annex baltic nations that are already puppets. Maybe though for balance if you use decisions to annex the Baltics, the armies are disbanded (which to my knowledge is what happened in real life) of the Batlic nations to help provide balance.
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