“It's sort of like the guy said, Justice Potter Stewart, when presented with the opportunity to rule on whether something was obscene or not, he said, I don't have to tell you what it is; I'll know it when I see it. And I think it's a lot like that in combat. If you were to ask somebody before he went in, 'Are you going to be able to acquit yourself honorably?' he'll say, 'Yes'- without knowing what that circumstance will be.”