Justice and Expediency
Only Aristotle uses the word "justice" in two radically different senses. He distinguishes between general and special justice. By justice in general he means justice as one of the four cardinal aspects of virtue, the other three being courage, temperance, and prudence. The morally virtuous man is a just man, an as such he is a temperate man and one who is also courageous and prudent.
By special justice, Aristotle means fairness in exchange and fairness in the distribution of goods. Fairness in exchange is commutative justice, and the other aspect of fairness is distributive justice. Fairness is the special justice that is be found in just laws; and it is in connection with the justice of human-made or positive law that Aristotle introduces the notion of equitable dispensation from a strict application of law to difficult cases. In the Anglo-American tradition of the common law, courts of chancery and equity provide such as dispensations by the Lord Chancellor in Great Britain and by a similar official in some United States jurisdictions.
Machiavelli tells us that the prince should be just in the use of power, but if a just use of his power is not expedient, then he should be expedient in his effort to be a successful prince. The ideal use of power occurs when ruling justly is also expedient. But when that is not possible, Machiavelli says, then the prince or anyone else with ruling power must be unscrupulous and use what ever means will succeed in getting or keeping power even if the means employed are unjust