Everyone has a good idea of what discipline looks like in an enlisted soldier. He takes care of himself, his gear and his comrades, he trains diligently, responds quickly to orders, looks you in the eye when he speaks, and keeps a good lookout.
But I don't think we have a good idea of what discipline looks like in a general. I would begin with this list of characteristics or rules of the road for flag officers:
— Thinks of himself as a steward of his profession, rather than as a member of a mutual protection guild.
— Rewards success and relieves incompetents in his command after giving them a fair chance.
— Enforces standards for his peers as well as his subordinates, and is transparent in these efforts, explaining what he is doing and why, and not just on a "need to know" basis.
— Understands that it is his duty to speak truth to power (in a respectful manner, and mainly on matters of importance, rather than as a constant burr under the saddle) but then, when the decision is made, executes lawful orders without griping to subordinates or leaking to the media.
— Seeks to surround himself with officers and other advisers who can think critically, but understands that it is his job first to think, and that the task cannot be farmed out to "the 50-pound brains."
— Strives to ensure that he is not only trained as a general, but educated as one. (Training prepares one for the known, education for the unknown, which is the bulk of what a senior officer must deal with in the chaos of war.)
— Doesn't do his subordinates' jobs. Turns off the "Predator" feed after a few minutes. Focuses on his level, and pushes decision making down as far as possible. Only does the jobs that only he can do.
— Doesn't complain about lack of "bandwidth" because he realizes it is part of the job of a general to manage his time and inbox in order to give himself time to think. Understands that if George Marshall could run World War II and still leave the office by 5, he can run Camp Swampy without burning out subordinates — or second-guessing their every move.
— Doesn't abuse his power. Watches himself on that account. Welcomes loyal dissent, and cultivates an atmosphere of trust that rewards subordinates for expressing doubts and concerns
— In retirement, doesn't drag his service into politics but is free to be involved in politics if he doesn't use his former rank or service affiliation. In retirement, doesn't go off to work in the defense industry and sell stuff to his former subordinates.
— In retirement, if commenting as an expert on TV, learns to say "I don't know," if he doesn't.
— When in doubt, he asks himself "WWGMD?" ("What would George Marshall do?")