The track record of military men who were POTUS is not impressive. Nothing grows under Bushes is an example. They also are (surprisingly) no better at managing/winning wars but like most POTUS's expert in foreign intervention and getting involved in them with no goal or exit strategy along with providing limitations/hurdles to the Pentagon.
I had respect for Powell as a military man but he was a Democrat at heart and not so well suited for political accomplishments.
I offer military men excel at their careers and politicians excel at theirs (rare); repetition here but the Pentagon and White House should have strict separation/protocol, that is the Administration/Congress declares war, states the goal, then gives it to the Pentagon/Military to fulfill while they keep their noses out of it. Troop strength, withdrawals, tactics, timing, level of power used/required are functions of the military, not civilians who are in/running for office or needing fodder for their campaigns.
My guess is that if Military men were given a mission without the stunningly ignorant limitations of politicians and void of political motive, our conflicts would be settled in a very timely and successful manner, foreign nations would take note, and foreign policy would be much more simple.