[redmajor12]

Maintaining NATO also ensures American hegemony over Europe and potentially the most disruptive global competitor. It may be expensive, but we know that left to their own devices the Europeans are wont to start a war amongst themselves, over some trivial border dispute, and then involve the rest of the world in it. So it's cheaper in American lives and material this way.

[ben_w]

That may be the predominant American belief, but I would point out that about over half of Europe — by population, making the zone larger than the USA — now has borders slightly more porous than the ones between American states.

https://en.wikipedia.org/wiki/California_Border_Protection_S...

https://en.wikipedia.org/wiki/Schengen_Area