[MRM]

I believe this is an isue that is well settled under international law. The answer is that you can strike in certain situations. The overriding factor is that all reasonable precautions must be taken to minimize civilian casualties.

The question of whether you can strike at all is one of proportionality. If the bunker is Hitler's and it will shorten WWII, you can strike after taking whatever precautions that are possible to minimize civilian deaths. If it is just a run of the mill comand and control structure in downtown Syria and you're in a sporadic battle with the Syrians but not a complete hot war, you probably can't.

The question of proportionality decides whether it is permissible, but at all times you have to do what you can to minimize civilian deather.