At the root of Niebuhr's thinking lies an appreciation of original sin, which he views as indelible and omnipresent. In a fallen world, power is necessary, otherwise we lie open to the assaults of the predatory. Yet since we too number among the fallen, our own professions of innocence and altruism are necessarily suspect. Power, wrote Niebuhr, "cannot be wielded without guilt, since it is never transcendent over interest." Therefore, any nation wielding great power but lacking self-awareness - never an American strong suit - poses an imminent risk not only to others but to itself. Here lies the statesman's dilemma: You're damned if you do and damned if you don't. To refrain from resisting evil for fear of violating God's laws is irresponsible. Yet for the powerful to pretend to interpret God's will qualifies as presumptuous. To avert evil, action is imperative; so too is self-restraint. Even worthy causes pursued blindly yield morally problematic results.