"Any military commander who is honest with himself, or with those he's speaking to, will admit that he has made mistakes in the application of military power. He's killed people unnecessarily—his own troops or other troops—through mistakes, through errors of judgment. A hundred, or thousands, or tens of thousands, maybe even a hundred thousand. But… he hasn't destroyed nations. And the conventional wisdom is don't make the same mistake twice, learn from your mistakes. And we all do. Maybe we make the same mistake three times, but hopefully not four or five. But there will be no learning period with nuclear weapons. You make one mistake and you're going to destroy nations."