Well it depends on what countrie "we" are. If "we" are the USA then we will most likely have Great Britain and such. If "we" are china then "we" will have north Korea and other Communists.
Us: Germany, UK, US, South Korea, Japan, Maybe France? Enemy: China, North Korea, Maybe Vietnam?
Canada would probably be on our side as a supportive force. Spain, Australia, Poland, Romania, and Italy too.
Russia would probably be neutral as an army, attacking whoever attacks them first, maybe a few spec op soldiers fighting alongside NK at the start. If we attack them, make them mad, they'll fully back NK, but they've moving away from communism, so they might even be on our side. Depends on what they'd gain from the war.
China would likely be as neutral, staying out of the war as long as possible, with some spec ops supporting whoever Russia's supporting. They've got an alliance.
Name one country thats 'selling itself', how do you even sell a country? thats not even possible?!
Greece, they are in so much debt that they started selling their islands to rich people, it's estimated that they have sold about half of their islands already.
I'm guessing WW3 will be another Korean War. NK is still fully militarized and tensions with SK are high. SK's military is also growing rapidly, it's just not as fanatical as NK's.
Man if Russia somehow in someway goes to war with us everyone is screwed including them.
The only way that would happen is if we attack them first. We're almost pals with Russia now. They're getting friendlier with Europe and are turning away from the Stalin's views of communist extremism which they once supported. They're not at quite the level the US has with France or GB, but they're getting there. Right now they're about neutral and will likely follow China's lead. China will likely do nothing because a war wouldn't do them any good. Both China and Russia would probably stay out of it until one was attacked, they'd both then side with whoever's against the attacker for revenge. It's kind of like if Mexico invades the US, we wouldn't want to fight them, but if they're attacking on our soil, we'll stop them.