国会在《战争权力法案》里授权白宫只在一种情况下可单方面发动战争，就是当国家实际面临迫在眉睫的危险时，可为“击退突然袭击”而以武力回应。
The Congressthrough the War Powers Act provided the executive with an exception tounilaterally respond only when the nation was in actual or imminent danger; to“repel sudden attacks.”
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