A suite of values-soaked abilities
The ancient Greeks created most of our vocabulary of virtue and saw virtue as central to politics. In fact, it was wrestling with the question of the kind of leader a community required that led them to investigate virtue, and that made virtue a practical, not merely a philosophical, consideration.
Virtuemoral and physicalwas to the Greeks a force, a capacity to do something, a personal power that enabled one to influence and shape oneself and one's community for the better. Virtue was practical, specific, and verifiable. The Greeks saw virtue as intimately connected with character, which can be defined as the working out of values in actual lifevalues livedthe intersection in the everyday world of stated values with choices and actions. For the Greeks it was meaningless to talk about values (think "family values" or "justice for the poor") apart from concrete actions that render those values visible and useful. And such actions were only virtues if they were recurring, becoming so ingrained in a person's responses to life that they were moral habits, reflexes, something that flowed almost automatically from one's essential nature. Virtue was not a given of birth or instinct, but must be learned and reinforced (hence, education centered on training in virtue).
Virtue is a suite of values-soaked abilities that in active combination form a person's character and give shape to a life. Our choices and actions both reveal and reinforce our character. You cannot judge whether a person will be a good leadera good Presidentwithout knowing and evaluating his or her characterhow life has stamped or marked them. A President is, among other things, a decision maker. Decisions flow out of values and experience, that is, out of character. The classical virtues, embraced by Greeks and Romans alike, are prudence (practical wisdom), justice (fairness), fortitude (courage), and temperance (moderation). They not only thought these desirable and useful, but also believed you could not be fully human without them. Each of the four virtues makes the others possible, and a lack of any one of them renders the others ineffective. Courage without wisdom is mere foolhardiness. Justice not backed up by courage is mere wishing. And any of the other virtues is vitiated if one lacks the self-control found in moderation. Virtue involves the whole personintellect, emotion, will, values, actions.
The other great source of virtues was Judeo-Christian, especially the virtues of faith, hope, and love. The medieval period inherited both traditions, kept virtue at the center of education, and embraced these seven as "the cardinal virtues."
So how does any of this help in choosing a President?
From courage to temperance
Let's start with the virtue perhaps most universally acknowledged and admired: courage. In premodern times, the courage of a leader often had to be physical. In the last 500 years it is more often moral. Moral courage is the ability to do what's right even when it is deeply unpopular, even dangerous. Courage is only found where there is the genuine possibility of lossloss of friends, reputation, status, power, possessions, or, at the extremes, freedom or life.