you are right about the possibility of mayhem with lone rangers (the Norway Shooter would also qualify). I was wrong. What I would now say (having been corrected) is that whether they kill a lot of people or not, they are then police problems, not military problems. No war needs to be launched to stop such attacks and no war can do anything about them. State-sponsored terrorism is an entirely different problem and is a more logical target for state-to-state confrontation, pressure and even war (though the cost-benefit in favor of war may be relatively rare, dont you think?).
Something like that. As you can see, I am making this up as I go along. I aim to learn.