[jabl]

Wars aren't fought by militaries who want to demonstrate the latest military toys (one hopes, at least), but to achieve policy objectives. So of course the politicians decide what the military is allowed to do. Unless we're talking about a military dictatorship, though in that case it's maybe more accurate to say that the military high command has taken over the policy functions of the state rather than the military existing in some magic policy-free environment.

Or to quote von Clausewitz: "War is not an independent phenomenon, but the continuation of politics by different means."