It should be an obvious point that in democracies, elected governments decide on policy and armed forces implement it. If you believe that armed forces should be doing the deciding--whether because of their greater expertise, or the moral superiority that comes from their greater willingness to sacrifice--then you are not a democrat (small d), but a militarist. In democracies, elected governments can certainly let their armed forces down. They can do so, for instance, by giving them a job and then failing to provide them with sufficient resources to accomplish it, as many argue the Bush administration has done in Iraq. But elected governments -- and last I heard, our own included something called the "legislative branch" -- cannot by definition let the troops down by debating policy, or changing it. This is the government's job. It can do it unwisely, but the fact remains that the troops' own job is simply to carry the policy out, however misguided it may be.Read it here.
I have been arguing this for a long time.
On the one side I have argued that the proper role of the armed services is to serve, not to initiate or direct policy. The opinions of military men and women should be respected, but not deferred to. It is the same with the civilian agencies, and that includes the intelligence services. All too often bureaucrats [or "professionals" as they style themselves] take it upon themselves to attempt to shape policy and in doing so engage in dubious, illegal, even traitorous, acts.
And of course the converse is also true. In our democratic political system policy decisions are legitimately made by elected officials or their representatives. No other credential is valid.