The surface of the moon is an awful lot of territory to claim by any entity here on earth, and that includes any one nation.
The moon is a much more hostile environment that even Antarctica, and much harder to keep a continuous presence there. But it probably makes an excellent field of battle, as it would be difficult to cause much in the way of collateral damage on the moon itself.
But as high ground, it could keep most opposition on the surface of Earth suppressed.