You are never going to win that argument against the military, unless you are able to come up with a better way to deal with the terrorists that doesn't put US soldiers at risk.
As for the civilian deaths - well there are always civilian deaths for military action.
I'm not trying to win an argument with the military. Nobody wins an argument with the US military. It's the most powerful organization that exists, if you exclude the leaders to whom it is accountable. But that doesn't change the moral and legal facts, which are pretty clear.
As for the civilian deaths - well there are always civilian deaths for military action.