North America versus Europe - who would win in an all out war?

[binary solo]

Depends who's invading who. The invader always has a disadvantage because the general population is against you, and you have to keep supplying material and people from your home base. I think Viet Nam, and to some extent Korea proved that a population motiviated to kick you out is worth a great deal for the home military. And the Atlantic is a mighty big body of water to cross with the home team just pot shotting your ships with missiles without having to get into Naval war until the invaders get close to the coast, in which case land based support will augment the home side's Navy.

Of course crossing from Russia to Alaska (or vice -a- versa is much easier. I think Europe would have an easier time of it, because there's less distance to cover before the invading force reaches anywhere important. Whereas North Americans forces have a shitload of pretty empty Russia to cross before it can start laying siege to the important cities of Europe. But in both cases a gradual retreat with home side supply lines getting shorter, and invader supply lines getting longer, and harder to defend from flanking hit and run attacks, makes it very hard to achieve a winning position.

So at the end of the day both continents are too big and difficult to invade and hold.