Im mostly joking but still I think there are better options then the classic “Russians invade Europe while the West and the US try to stop them”. Why not have a scenario where China is trying to invade the south china sea with one power being China, another being the US, and then one being an amalgamation of Vietnam, Philippines, Malaysia and Indonesia, a south-china sea alliance if you will. Or how about one where Russia is really weak and can only buy infantry and is facing an invasion from the south by an amorphous Muslim/terrorist organization and the West (NATO) and the US have to try to save Russia before the terrorists get to Moscow and gain control of Russia’s nuclear arsenal?
Why not have a Scenario, where fascits or ultra nationalist red necks take over America.
And AMERICA invades the free world, starting with Mexico.
You could have a whole political system, where free nations like Canada, or the UK, could either JOIN the American Conquest, or RESIST it. A “if you’re not with us, your with the terrorists” kind of mentality.
Each nation/power, would have independant victory conditions, which if met, call the game to close. Points compared. Winner takes it all!
The more nations that join the American Player, the less points the American player gets at the end if they win - but they’re not likely to win alone. And of course, any countries that try to retain -some- independance by joining the Americans, would also lose points for themselves, though ensuring a higher possibility of securing their OWN goals.
That, or a multinational battle for control of the SPACE around earth.