Discipline

This is what the British Army has to say about it. I think most of it has come out in the comments on the previous post, possibly with the exception of the bit about military law:

The Army is, of necessity, an hierarchical institution, which must be structured in peace as it is for war if it is to be trained and ready to deploy at short notice on operations. To be effective on those operations, the Army must then act as a disciplined force. Commanders must be certain that their orders will be carried out, and everybody must be confident that they will not be let down by their comrades. Lives may depend on it, as may the success of the mission. Good discipline also helps to conquer fear. The best discipline - which the Army expects from every soldier -is self-discipline. This comes from a sense of commitment and loyalty, and a readiness to put the needs of others, and of the mission, ahead of self-interest. For example, to keep on fighting when in danger or isolated, to stay alert on sentry when tired, cold or wet, and to keep going when frightened or exhausted.

Because discipline is so vital to success on operations, commanders must be able to enforce it when necessary. That requires clearly understood rules and a military legal system which can deal with offences such as absence, desertion or insubordination which are not found in civil law. And if it is to work in war, such a system must be in place in peace, for it cannot be turned on and off at will. Discipline must therefore be rigorously but fairly upheld by all those in positions of authority, and self-discipline must be deeply rooted.