How to mod nations themselves?

[Mobhack]

You don't. We do - all that stuff is buried deep in the game code.

All that you as an end user have available is the Mobhack editor, to change the existing nationalities unit, weapon or formation data. Plus, you can do some hacking of the flags and other graphics with SHPed, should you know what graphic is what.

But "Russia" and "USSR" and when the new Russian flag replaces the Soviet one is hard-coded. Same for the air superiority tables, counter battery, leader ratings and so on.

Cheers
Andy