The cost of having troops in certain countries is a completely legitimate thing to negotiate over.
How much more significant is it in housing them in the US, or wherever else they're likely to disperse them to?
That expense is payed for by the American taxpayer, and if it's determined that the benefit of having 50 000 soldiers in Germany isn't worst the cost, either have the Germans pay more or send the soldiers home. Those soldiers aren't crucial to the defense of Germany.
I'm kind of shocked that you think they're in Germany for the defence of Germany, and not as part of a broader American policy that is tied to their foreign policy. Those troops aren't in Germany to protect Germany, they're in Germany so the US can project power anywhere in the region on short notice. For example, their bases in Germany handled a tremendous amount of the logistics required for the US adventures in Iraq and Afghanistan.
If it is determined that the benefits of having troops in S Korea or Japan isn't worth the cost then have them pay more or send the soldiers home. And yes yes, people will moan about how the USA benefits from having a military footprint in these nations but at the very same time, you wont see any other country happily filling the void. You wont see French soldiers in Germany, you wont see Canadians in S. Korea, you wont see the Brits in Japan. So the benefits cannot be that great.
You seem to want to continuously ignore America's unique standing in the world, that has existed since 1946. You won't see any other country filling that void, because no other country has the capability to fill that void, not because they don't have the desire to fill that void. Once upon a time though, Britain (and to a lesser extent, the other colonial powers) did in fact fill that void. China has started following the US example by developing the ability to project military power far outside of it's borders. It's what all great powers have always done. It's a requirement if you want to build or maintain your hegemony. One has to wonder that if the benefits aren't that great, why has every great power in human history followed more or less the same blueprint? The Assyrians, the Persians, the Macedonians, the Romans, British, etc, etc, etc.
It's a legitimate thing to talk about and to negotiate. Someone is paying for having soldiers in the country, if the American taxpayer deems that it's not getting fair value for what it's spending, then they should leave.
The American taxpayer truly doesn't understand the benefits the US has received from 70 years of empire. Largely because the spoils go to the class of people they tend to approve tax cuts for.
Strategically, very little changes. The Russians wont invade Europe because 50 thousand Americans aren't in Germany, the North Koreans aren't going to invade South Korea because the American soldiers are gone and the ...Chinese? Russians? I don't know who plans to attack Japan, but they wont do it if the USA decides to leave.
What changes is the American ability to influence the decisions of foreign goverments with shows of military force. That's more or less the entire purpose behind the aircraft carrier program, no?
