Turns out I'm color blind. I already had the top secret clearance, ended up as a quartermaster (QM) for Patrol Coastal Crew Charlie at Naval Amphibious Base Little Creek in Virginia Beach, under command of SOSCOM (Special Operations Support Command).
A lot of driving around spec ops units on a RHIB (Ridged Hull Inflatable Boat) up and down the Um Qasr river (which is actually more an estuary and canal system, and actually has a lot of different names as it shifts... but that's another story - everyone just calls it 'Um Qasr').
Bottom line, the military will put you where they need you most. Smart people get put into advanced training for very technical ratings. I would probably be working in a nuclear power plant today had I been born with normal color vision. Such is life. Smart people are too rare to waste on shit like infantry. There's plenty of people that can hold a rifle.
Nitpick: the infantry needs intelligent people too, especially in the officer ranks. McNamarra's Morons suffered massively-higher casualty rates than "normal" draftee infantry, for example.
I'm not sure I agree that those are the only situations where wars and battles occur - maybe in great power conflicts but was there really much diplomacy or negotiation before the U.S. invaded Iraq?