Of that 800 billion, where is the money spent? If it goes to US military/industrial complex, it is basically a creator of US jobs.
So it doesn't cost the US anything.
So it doesn't cost the US anything.
[1] https://en.m.wikipedia.org/wiki/Parable_of_the_broken_window
It also is meant to keep American industry active (to some degree) in case it is needed.
The Europeans couldn't deal with a few land pirates practically in their backyard.
The US isn't sending sad cases over to Japan to cash welfare checks.