The conservative thinkers, writers and political advisers whom I have spoken with over the past week have struggled to give a simple definition of “character.” Perhaps character is like pornography — we know it when we see it.

Princeton professor and conservative thinker Robert George has some useful examples: “John Adams, even as a politically ambitious 35-year-old lawyer, was willing to represent the British soldiers in the Boston Massacre case, despite the all-too-real possibility that it would ruin him. There was a manifestation of character.” George also has a more contemporary example from his work in the 1990s for Robert P. Casey, the pro-life Democratic governor of Pennsylvania. He recalled, “The Republicans had nominated a pro-choice woman named Barbara Hafer, who was the state’s auditor. Before the final debate, Casey’s campaign manager (a guy from Louisiana named James Carville) told him that unless he ‘softened’ his position on abortion, Hafer would defeat him. ‘Then I’ll retire and play with my grandchildren,’ Casey said. Of course, this conversation took place in private, so the public didn’t know about it; but it told me that Casey was for real: He had character.”

We don’t have an Adams in the 2012 presidential race and maybe not even a Casey, but the examples are nevertheless helpful. George summed up: “What the Adams and Casey stories illustrate, I believe, is the importance of virtues such as courage, constancy, self-possession (a.k.a. self-discipline) and dedication to causes one believes are larger and more important than oneself. In an age of narcissism, these virtues are in short supply, so I suppose we shouldn’t be surprised that so few politicians seem to possess them.”

It is difficult to rank character traits in order of importance. Peter Wehner acknowledges, “Different moments and different challenges may demand different character traits. Sometimes courage is what is most necessary; other times perseverance; other times honesty; and still other times loyalty and fidelity. All of them are important, but the hierarchy of their importance can slide depending on whether, say, a nation is at war.” Taking off his philosophical cap, Wehner recalls the three administrations in which he has served. He tells me that based on that experience “if I had to settle on one quality above the others, I would side with the ancient Greeks and opt for prudence, which encompasses practical wisdom, insight and knowledge. It is, St. Thomas Aquinas wrote, ‘right reason in action.’ Prudence plays a vital role in terms of guiding and regulating all the other virtues. For example, courage in the pursuit of an unwise course of action can lead to a catastrophe. So I consider prudence to be the auriga virtutum, the charioteer of the virtues.

Bill Bennett, who has served and observed a number of presidents, pointed to the hedgehog and the fox distinction. The hedgehog knows a few things and does them with determination; The fox races from one distraction to another. The former is desirable especially in a president. “It is focus and keeping yourself in bounds,” he says. Trying to “play to many parts” is a recipe for disaster. Indeed, much of what Bennett describes amounts to self-contained confidence. The guy who “always has to be the smartest kid in the class” is a recipe for trouble. Moreover, an insatiable thirst for approval is a danger as well. He says that part of “manliness” is the not needing “constant reinforcement.” (Unfortunately, that’s a rare quality in politicians.)

There seems to be some agreement that religious faith is not necessarily indicative of good character. Bennett finds it useful to realize that “religious membership” isn’t the determining factor. Wehner likewise counsels, “Placing too much emphasis on the external habits of religiosity, like church going, can be a mistake, though of course it’s not necessarily so. What matters is the condition of the human heart, not the outward symbols of faith. The chief articulator of this view may well have been Jesus himself. And of course faith is not necessarily synonymous with outstanding character. People of good character can have no religious faith — and people of faith can be corrupt.”

Much of what philosophically inclined conservatives think of in moral terms, experienced White House advisers explain as simply smart management. A senior Republican strategist said, “When you are president of the United States you can’t always be the prime mover. You have to make decisions.” He joked, “You have to decide whether to shoot down other people’s spitballs.”

Political campaigns often veer off into a battle of the white papers and a game of catching your opponent in more inconsistencies than he can find in your record. But that and delight in who can skewer the incumbent president in the most amusing fashion may not be as important as the core character of the person who will make thousands of decisions, some on issues we haven’t even thought of. It was paranoia and lack of honesty that did in Richard Nixon. It was lack of self-restraint that wrecked Bill Clinton’s second term. And it was basic decency, humility and focus that enabled Ronald Reagan to become the most successful Republican president of the 20th century. (Sorry, I don’t buy into the TR fetish.)

To get a president who embodies critical virtues, voters have to agree that these virtues matter. They have to make the effort to discern during the tumult of the campaign who is the person most likely to be worthy of the trust that will be placed in him or her. Bennett warns conservatives not to let up on their own side. “If we don’t tackle hard in practice,” he warns, the general election may be disastrous. He says bluntly, “We better do it now.”