Machiavelli equivocates on the term vice, referring to it in instances that (1) are devastating to a prince’s rule, and (2) actions that are viewed to be immoral, but that nevertheless seem to further the reign of the prince. The second category seems to be an anomaly, since these elements are usually though to be virtuous. Nevertheless, in a public/private split, Machiavelli recognizes that the actions are both virtuous and vicious, in the sense that although they bolster the prince’s reign, they are regrettable.

-Necessity is the ultimate arbiter
-Men are beasts, since the laws that should appeal to men as men are most often not efficacious. Thus, given human nature, the use of force—and the use of it well—is a necessity.
-If all men were good (moral), the necessity of adopting the fox and lion would not be useful, but since men are not good, this justifies deceiving them and employing the wiles of the fox and the strength of the lion.
-Machiavelli does not show regret at war. When  he does pause, however, is not on war itself, but at the means used in conducting war, which he thinks are unbecoming of a prince, regardless of whether or not they are useful—another equivocation (tis time on ‘virtue’ rather than vice) on virtue. (35). These methods are ‘virtuous’ in the sense that they acquire empire, but not in the sense that they violate glory.
-Virtue: conformity to necessity within the bounds of glory, and for Machiavelli, glory seems to be the term under which a hint of morality can slip in, so he does not completely separate morality from politics; he merely severely limits its practical application to politics, for to act morally (given the fickle nature of his subjects) would be the antithesis of rightly-ordered, stable rule.
-Choose/prefer good over evil, but do not hesitate to part from good when necessary.
-The fact that people in general are wicked is the sort of justification that Machiavelli uses for his doctrine of necessity. It is regrettable, but a brute fact about human nature. The first wrong justifies the second wrong, for Machiavelli seems to think that if it were not for a corrupted human nature, then none of these methods recommended would be permissible. They would be judged immoral and done away with. It’s a necessity, but a bitter one, which is praised through clenched teeth. It is not a wholesale embrace of evil.
-He frames it in terms of departure from and forced to, which supports my interpretation that morality is the default position, but the facts of human nature literally compel a prince into virtu, and virtu is given some moral justification as well, since a prince’s terrible rule would result in the absence of glory and honor and the presence of anarchy—human nature unchecked and unbounded by law (77).
-Fortune gives opportunity for virtue.