As displayed in this thread, most people who haven't been in the military have this image of mindless killing machines, but you're right that servicemen, officers in particular, are taught critical thinking skills, ethics, and morality*+, which are essential for the ability to make good decisions and be good leaders and are not taught anywhere else. The first half of my undergrad education, at the Naval academy, included weekly leadership/ethics seminars, leadership and ethics classes, weekly speeches by prominent leaders (Colin Powell, Janet Reno, Jim Lovell, etc.), and upperclassman-based instruction (that one's hard to describe). The second half of my undergrad education at Drexel University included one engineering ethics class (which is a relatively new thing) . There is no other place to learn good leadership skills than in the military. That's why, to me, military service is the single biggest qualification I look for in leaders. There are very few people who haven't been in the miltiary who are capable of being real leaders.
*Liberals and young people tend to be moral relativists, as a default belief (along with the 'anything is possible' belief is the 'right and wrong depends on the individual'). One amazing experience I had at the Naval Academy was actual discussions about morality. Most people have these ideas in their heads about morality that they never actually explore - they think something, it sounds good, so they believe it. But when you start to actually discuss it, argue it, and think it through, people realize that the standard assumption of moral relativism is actually defunct. It is wrong, obsolete, and it doesn't work in practice. I'd guess that when we started these seminars, more than 75?% of midshipmen were relativists. By the end, after being forced to think about it, more than 75% were moral absolutists/realists. This is the kind of thinking I want from my leaders. The charismatic, but empty leadership displayed by Obama will be a big problem if the country ever needs real leadership@.
+Caveat: the type and level of this training is not consistent, even in the military. In particular, a re-emphasizing of the need for officers to be moral free-thinkers occurred after the My Lai incident, which happened after McCain was captured. So it is possible that midshipmen today receive more leadership training than McCain did when he was at the Academy.
@Clinton will likely go down in history as an above average President. What will prevent him from being considered a great or even exceptional President is his utter lack of real leadership skills. Clinton relied heavily on public opinion polls to make his decisions and surrounded himself with mindless sycophants who couldn't actually help him make decisions. He lacked morality/ethics and didn't think/lead for himself. He was lucky enough to be President during a time where the US needed perhaps the least leadership in its history (with the exception of doing nothing about the rising terrorism problem). Bush, on the other hand, will go down in history as a bad President who nevertheless had good leadership skills, which enabled him to start an unnecessary war and get re-elected. He got people to line up behind what was otherwise an unpopular vision.