there is no part of the Earth’s surface that you can’t hit using cheap magnetic accelerators and lunar rocks serving as incredibly powerful artillery. Practically unlimited ammo supply and if you absolutely have to, you can power the accelerators by solar panels. Anything coming out of Earth’s gravity well will be seen coming and be the recipient of several kinetic kill projectiles.
Control the orbitals (in this case by setting up a bombardment system on the moon), you control the planet.
Straight out of Heinlein's The Moon is a Harsh Mistress
Yup. Heinlein wasn’t wrong.