I'm looking at it from an out of character perspective here, just to be clear.
Really, I'm not so sure about the house rules in this PBEM. While they do provide a peaceful alternative to "winning" this PBEM, they also seem unclear on certain points and stifling on others.
What nations are "untouchable" per house rules is just one aspect of this.
Also, the selection of playable nations and what cities/countries they hold seems a bit... off. Putting the NATO together into one huge nation seems hard on everyone else (and a bit on me as well, but purely from a "having hundreds of units to move around each turn" perspective ), it should probably have been divided into a US-NATO and a Euro-NATO which are allied. Similarly, not having Japan or Australia in one of the playable nations while Brazil is a playable nation seems odd.
Quite frankly, I'm starting to dislike this scenario due to these flaws. It's only turn 2, but could I ask you guys to check out Academia's Iron Curtain? While the graphics may look dated, I think it's a better take on the Cold War. This is probably an old version, I think there's a newer one around but the scenario league page for it is blank.