"To hard-core nationalists and neoconservatives, the acceptance of limits suggests retrenchment or irreversible decline. In fact, the reverse is true. Acknowledging the limits of American power is a precondition for stanching the losses of recent decades and for preserving the hard-won gains of earlier generations going back to the founding of the Republic. To persist in pretending that the United States is omnipotent is to exacerbate the problems that we face. The longer Americans ignore the implications of dependency and the longer policy makers nurture the pretense that this country can organize the world to its liking, the more precipitous will be its slide when the bills finally come due.
A realistic appreciation of limits, on the other hand, creates opportunities to adjust policies and replenish resources - perhaps even to renew institutions. Constraints subject old verities to reconsideration, promote fresh thinking, and unleash creativity.
Andrew J. Bacevich, The Limits of Power: The End of American Exceptionalism, 174.