Only with humility tread this road

The second item in this Glenn Greenwald post captures exactly why an individual's military history (or lack of) should carry special weight when considering whether they're fit to influence the deployment of the military. Those lacking in certain experience often can't fully understand the gravity of their actions, and when you're a President, Vice-, SecDef, or Sec of State, that endangers not just individual lives at both ends of the spear, but the degree to which our country exemplifies its values. Here's what he says based on the Murtha situation:

But what incidents of this type do underscore is that wars are not something that are to be routine or casual tools in foreign policy. The outright eagerness and excitement for more and more wars that we see so frequently from some circles is not only unseemly and ugly unto itself -- although it is that -- but it is also so reckless and unfathomably foolish. Every war spawns countless enemies, entails incidents which severely undermine a nation's credibility and moral standing, ensures that the ugliest and most violent actions will be undertaken in the country's name, and, even in the best of cases, wreaks unimaginable human suffering and destruction.

Even Greenwald's description of war being a casual tool falls short; war can not ever be a tool of policy. It must only ever occur due to the complete failure of policy.

Here's another good statement about Murtha from John Cole at Balloon Juice.