I don't profess to know whether our leaders believe in God or are truly "Christian" in any sense of the word, but anyone today who opens their mouth and purports to speak of "virtue" had best understand what the Judeo-Christian tradition has contributed.
Christian "character" education comes through the teachings of "the Law" --the teachings of the five books of the Torah, as interpreted by Jesus in the Gospels-- and the admonitions of "the Prophets". This extremely complex and comprehensive code of conduct cannot validly be reduced to Paul's ascetic virtues (faith, hope and charity) nor his doctrine of salvation by grace through faith. It can be summed up by the Great Commandments: Love God, and love your neighbor as yourself. (Matt. 22:37-40).
"Thou shalt love" (αγαπησεις : agapeseis, the imperative form of agape) is the sum and substance of the Christian virtues. Jesus left no doubt that "agape" was not merely a feeling or a contemplative state, but rather a spirit to be expressed practically in our daily activities, in the tradition of "the law and the prophets". A society founded on "the law and the prophets" is a society in which violent, selfish, and careless urges are everywhere confronted with rules and admonitions to behave with compassion and justice. No amount of perverse biblical literalism can erase the eloquent pleas for social justice by the Prophets:
You trample on the poor and force him to give you grain. Therefore, though you have built stone mansions, you will not live in them; though you have planted lush vineyards, you will not drink their wine. You oppress the righteous and take bribes and you deprive the poor of justice in the courts. Therefore the prudent man keeps quiet in such times, for the times are evil.
And so on and so forth for hundreds of pages. These are the Scriptures which live in the work and words of true Christians like the Rev. Dr. Martin Luther King, Jr.. Anyone who doesn't recognize "Christianity" in all of the liberal social reform movements of the past two hundred years simply is not familiar with Scripture, except the easily misunderstood Epistles of Paul.
The "saved by grace through faith" dogma is a Pauline invention, meant to explain Jesus' crucifixion as a sacrifice and address the fear of God's wrath with assurances of God's love of the fallen and disobedient. It does not answer the question, "How should we act?" and it wasn't meant to.
By contrast, the pre-Christian Greeks weren't worried about going to Hell, though Plato tried to introduce that concern in the Republic. The Greeks wanted to know how to be happy. Mostly, they believed happiness was to be sought in activity, in struggle, and Aristotle was no exception.
In Aristotle 's Nichomachean Ethics, σωφροσυν&eta (sophrosune: moderation) is a virtue in its own right, along with bravery, justice, generosity. While "moderation" in the sense avoiding extremes is an important theme in the discussion of ethical virtues, for Aristotle, ethical virtues are not the highest virtues nor even the virtues most conducive to happiness. True and perfect happiness is found in contemplative or intellectual activity, activity undertaken "for itself" and not for the sake of other things. Aristotle does not counsel denying or limiting oneself in the the activities which in themselves constitute happiness. Once you leave the dull world of actions undertaken merely for results (eating to satisfy hunger, drinking to satisfy thirst) notions like "moderation" no longer apply. In the end, Aristotle insists, the whole purpose and aim of military and political activities is to make time for thinking.
While contemplative types have adored Aristotle ever since, this sort of thing didn't sit well with the Romans, and they ditched it for Christianity, shortly after making Greece a Roman province. The Greeks, despite their artistic and philosophical achievements, never came up with a coherent social order, let alone "civic virtue" (which, as two Latin words, betrays a Roman origin).
As for "moderation", it hasn't withstood the test of time as an all-encompassing maxim. Lists of virtues have been popular through the ages, and usually include "temperance" and/or "moderation", though often just in reference to eating and drinking. Consider, for example, the list of virtues which Benjamin Franklin presented in his "Plan for Attaining Moral Perfection" (from his Autobiography). "Moderation" is anger-management: "forbear resenting injuries so much as you think they deserve." But reading Franklin's list of virtues (go on, read it! Here's the link, again) one is reminded of the specifics of the Bible; not the Aristotelian apotheosis and worship of happiness as "thought thinking itself".
Franklin, while he didn't believe Jesus was God, found Christianity useful, in a Machievellian sort of way. He once wrote to a friend:
As to Jesus of Nazareth, my opinion of whom you particularly desire, I think his system of morals and his religion, as he left them to us, the best the world ever saw or is likely to see; but I apprehend it has received various corrupting changes, and I have, with most of the present dissenters in England, some doubts as to his divinity; though it is a question I do not dogmatize upon, having never studied it, and I think it needless to busy myself with it now, when I expect soon an opportunity of knowing the truth with less trouble. I see no harm, however, in its being believed, if that belief has the good consequence, as probably it has, of making his doctrines more respected and observed; especially as I do not perceive that the Supreme takes it amiss, by distinguishing the unbelievers of his government of the world with any peculiar marks of his displeasure.
Scripture itself remains an excellent source of practical wisdom concerning civic virtues, eminently suitable for embarrassing the windbags of tryanny and ignorance. Recent history has provided Virtue with much more vigorous and sane champions, like Voltaire and Franklin. There's really no need to dig up Aristotle's bones and re-arrange them as our Hero of Reason.