Secure yet?

There are a total of about 47,000 U.S. troops in Japan.

Can anyone explain this to me?  It has been 67 years since the end of hostilities.  The Korean War ended, the Vietnam War is over. Yet we still feel compelled to keep 47,000 U.S. troops in Japan?

The Japanese people don't like them there.  Crime is up (hey, they are young and pretty much bored).

We are borrowing money from the Chinese to pay for troops to watch the Chinese.  It is total insanity.