Quarto
Unknown Enemy
Occupational forces, too. I mean, if you take a Kilrathi planet, you don't want to keep your precious Marines tied down.
Besides, planets are much bigger than the average theatre of operations... if you attack a planet that's got a lot of important targets, a large population, and large defences, you'll use Marines to open up a beachhead and then you'll throw in the regular Army. Planetary warfare doesn't need to happen frequently... the scale of combat makes the existence of a huge Army necessary even if you only attack one planet once every five years.
Regarding Naval Aviation, my own theory (which is not backed up by virtually any facts) is that Space Force was originally just planet-based fighters (essentially, space-capable fighters which defend the planet from hostile incursions, and attack any hostile capships that get with range). When it turned out - and even McAuliffe made this obvious - that huge, static planet-based fighter bases are a waste of resources, the Space Force got shifted onto carriers, while the Naval Aviation got relegated to light carriers (note - Bear was a Naval Aviator in End Run, as was, apparently, Lt. Comm. Chekhova), cruisers, destroyers and what few Naval bases there still were(eg., Perry, Ella). The original, static planetary defence Space Force role was given to InSystem Security (like Blair and Shadow) and in some places (Gemini, Border Worlds) to local Militias. Whaddaya think?
Besides, planets are much bigger than the average theatre of operations... if you attack a planet that's got a lot of important targets, a large population, and large defences, you'll use Marines to open up a beachhead and then you'll throw in the regular Army. Planetary warfare doesn't need to happen frequently... the scale of combat makes the existence of a huge Army necessary even if you only attack one planet once every five years.
Regarding Naval Aviation, my own theory (which is not backed up by virtually any facts) is that Space Force was originally just planet-based fighters (essentially, space-capable fighters which defend the planet from hostile incursions, and attack any hostile capships that get with range). When it turned out - and even McAuliffe made this obvious - that huge, static planet-based fighter bases are a waste of resources, the Space Force got shifted onto carriers, while the Naval Aviation got relegated to light carriers (note - Bear was a Naval Aviator in End Run, as was, apparently, Lt. Comm. Chekhova), cruisers, destroyers and what few Naval bases there still were(eg., Perry, Ella). The original, static planetary defence Space Force role was given to InSystem Security (like Blair and Shadow) and in some places (Gemini, Border Worlds) to local Militias. Whaddaya think?

. So, first things first...
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