Of course. And if an area is severely depopulated, one of the easiest ways to populate it and simultaneously discourage opportunism would be to plop a US military base down. "Easy" because it's doable, there are already bases, and protocols, and familiarity.
https://www.theguardian.com/world/2016/jun/19/thousands-prot...
The existing bases are in sparsely populated areas. Even so, they're deeply unpopular, mainly because the servicemen have a bad habit of raping and murdering the locals.
Adding more bases to boost the population would be political suicide.
An ideal scenario in my opinion, would be for the Japanese to automate a purely defensive military along with their workforce. Japan could go back to being that demon island that no one dares to invade.