The thing is, if you're planning a coup with military backing, you don't do it when your most rule-abiding, law-respecting general is in town. You send that guy to guard the Alaskan border or whatever, and instead recruit a general who's a maverick rules-breaker and who gets on well with you personally.
So the military should respect the constitution, but when it comes to a coup you'll get whichever general respects the constitution the least.
So the military should respect the constitution, but when it comes to a coup you'll get whichever general respects the constitution the least.