Let's be real here, Americans would start running Europe within 1 month of landing if they even moved back here.
Europeans are weak, effeminate and have no leadership qualities. Americans are aggressive, dominant and god-gifted alphas. Americans would turn Europe into a military superpower and start bombing some sandnigger tribe and invading Africa within 30 days of taking over Europe. They would also inseminate every fertile-age female from the southern Mediterannean shores to the fyords of Noway. And European betas would cheer them on because their women are getting bred by superior males of the same species.
Europeans have an inherit inferiority complex against superior American alphas and they feel threatened by their mere presence in Europe. This is why Europe has been historically hostile against Americans.