A fine summation of the merits of Machiavelli:
Wicked stuff. And yet Machiavelli is no sadist. Unscrupulous means are justified only if they serve one specific end, in the words of Kenneth Waltz, preserving “your power in the state and your state among others.” He does not advocate mindless violence or gratuitous cruelty—not because he is squeamish, but because they are counterproductive. Machiavelli thus counsels prudence as a core element of princely leadership.
What is most scandalous about The Prince—no less so now than when it was written—is Machiavelli’s apparent endorsement of the principle that “the ends justify the means”, however cruel and harsh these means be. As the author himself explains, “In all men’s acts, and in those of princes especially, it is the result that renders the verdict when there is no court of appeal”.
And then this advice:
Machiavelli’s contributions to the tradition of political realism are enduring. They include his admonition to take the world as it is, rather than it should be; his recognition that power and self-interest play a paramount role in political affairs; his insight that statecraft is an art, requiring political leaders to adapt both to enduring structures and changing times; and his insistence that the dictates of raison d’état may conflict with those of conventional morality. It is this last contention—that the public and private spheres possess their own distinct moralities—that remains so jarring today.