If there aren’t aliens camping out up there who have told us to get lost or if we’ve not already established bases and whatnot on the moon and if colonizing efforts continue to look like anything like they do on earth, then it will probably be the usual mix of corporate control and empire enforcement via the military. See Arsenal of
Hypocrisy, which, @Dog, demonstrates that the moon proper need not be defended so long as a force can control who gets on and off planet earth.
One scenario for colonization/occupation is the mining of helium-3 which potentially can provide abundant energy via cold fusion. A fictional example of a helium-3 mining operation is depicted in the recently released film Moon.
edit:: Treaties, of course, say no country can own the moon but say nothing of corporations. Also, space-based profits are not taxable.
Jesus Christ, I’ve turned into the comic book guy from The Simpsons.