Perhaps the first thing to note is that our Constitution is, to borrow a phrase from Hayek, a "constitution of liberty." Under it, the power of government over the people is checked and limited, and the people enjoy a large measure of freedom. But freedom can, of course, be used for good or for ill. Freedom can be used wisely or irresponsibly.

Like the other Founding Fathers, Adams recognized that freedom does not guarantee virtue; yet the maintenance of freedom and the cultivation of its cultural conditions require virtue. Freedom itself is placed in dire jeopardy when free people become corrupt or foolish. It is also put at risk when fear, absent the virtue of courage, induces them to abandon freedom for the sake of security--be it economic or physical.

So, virtue is one cultural condition of freedom, and it is necessary to the establishment and preservation of freedom's other cultural conditions. Beyond that, there are other social goods--essential aspects of the common good of any political society--that require virtue among the people. When freedom degenerates into what the Founders called "license"--a counterfeit of true freedom--these goods, too, are placed in grave peril.

All of this may be common sense, but it was a sense that was by no means common when Adams and his fellow Founders launched what they themselves understood to be an "experiment" in republican government and ordered liberty. And it is a common sense that, as the conditions of contemporary intellectual life have made all too clear, can be forgotten. Indeed, it is a common sense that can be derided and mocked by people who regard themselves as too worldly, sophisticated, and enlightened to believe in things like morality and virtue. So in the face of modern nihilism (sometimes, paradoxically, masquerading as the most high-minded moralism) the defense of Adams's proposition takes on a kind of urgency.

Is Religion Necessary for Morality?

Let's look at Adams's proposition regarding virtue in the context in which he asserted it. Here are his words:

But should the people of America once become capable of that deep simulation towards one another, and towards foreign nations, which assumes the language of justice and moderation, while it is practicing iniquity and extravagance, and displays in the most captivating manner the charming pictures of candor, frankness, and sincerity, while it is rioting in the rapine and insolence, this country will be the most miserable habitation in the world. Because we have no government armed with the power capable of contending with human passions unbridled by morality and religion. Avarice, ambition, revenge, and gallantry [by which Adams evidently meant sexual license] would break the strongest cords of our Constitution, as a whale goes through a net. Our Constitution was made only for a moral and religious people. It is wholly inadequate to the government of any other.

Among those intelligent, honest, and humble enough not to think themselves too sophisticated to agree with Adams that the common good and freedom itself depend on virtue, some will say, "Well, yes, virtue surely is required, but individuals--and even nations--can be virtuous even if they are not religious." So Adams, they maintain, should have said, "Our Constitution was made for a moral people, whether or not they are religious."

Are they right?

Adams was hardly alone among the Founders in viewing morality and religion as required for the success of their experiment with a constitution of liberty. In his Farewell Address, George Washington famously said:

Of all the dispositions and habits which lead to political prosperity, religion and morality are indispensable supports. In vain would that man claim the tribute of patriotism, who should labor to subvert these great pillars of human happiness, these firmest props of the duties of men and citizens. The mere politician, equally with the pious man, ought to respect and to cherish them. A volume could not trace all their connections with private and public felicity.

So far, Washington has basically said what Adams said. But the Father of our Nation then turned specifically to the question whether we, as a nation, could get along without religion:

Let us with caution indulge the supposition that morality can be maintained without religion. Whatever may be conceded to the influence of refined education on minds of peculiar structure, reason and experience both forbid us to expect that national morality can prevail in exclusion of religious principle.

I think this answer--which we have reason to believe was drafted by Alexander Hamilton and, I suspect, refers to Hamilton's political adversary Thomas Jefferson--is a good answer, though more can and should be said.

Personal vs. National Morality

The answer concedes that in the case of particular individuals, reason can indeed support virtue even in the absence of what he calls "religious principle." But he supposes that such persons are rare. Their minds are of a peculiar structure, and they are among the few who, on top of that, have had the benefit of a refined education. What he calls "national morality" cannot be sustained by a few such people, even if they exist. Reason itself, and experience, teach us not to pin our hopes on virtue ungrounded in, or unsupported by, faith in God. Washington, like Adams, believed that reason, given man's fallen condition, was a bit too uncertain a trumpet, and that human passions of the sort that compete with virtues and lead us into error and sin are too powerful for reason to reliably prevail over them.

Washington and Adams were, to be sure, men of the Enlightenment--believers in the power of reason. And their Constitution was one that would test whether "societies of men are really capable or not of establishing good government from reflection and choice, or whether they are forever destined to depend for their political constitutions on accident and force," to quote Hamilton's famous line from the first Federalist Paper. What's more, they certainly did not believe, as many ignorant people today seem to believe, that faith is the enemy of reason. But they did believe in the power and importance of faith and, indeed, in the harmony of faith and reason, when faith and reason are rightly understood.

So those of us who hold, as Adams and Washington held, that ours is a Constitution made for a moral and religious people, need not and should not deny that there are virtuous people, good citizens, among those of our neighbors who profess no religion, or for whom religious belief only hovers in the background of their consciousness.

Many do muster the moral resources to avoid falling into the vices that Adams and Washington rightly viewed as fatal, should they become widespread, to a free society. Some are among those citizens whose selflessness and patriotism would enable them to volunteer for missions in which they might give what Lincoln described as "the last full measure of devotion."

And yet, dare we suppose that liberty-sustaining virtues can survive if the great mass of people over a great expanse of time lose or abandon a sense of the transcendent, the spiritual, the more-than-merely-human source of meaning and value? That is a proposition that we should, as Washington warned, "indulge with caution."

The Moral Heart of the American Constitution

There is an additional reason for caution--a reason that goes to the distinctive nature of the American constitution of liberty. The Constitution bequeathed to us by men like Washington, Adams, and Jefferson effectuates a particular understanding of political order--one set forth with admirable clarity and candor in the Declaration of Independence. The moral heart of that understanding is the idea of God-given natural human rights.

We hold these truths to be self-evident, that all men are created equal; that they are endowed by their Creator with certain unalienable rights; that among these are life, liberty, and the pursuit of happiness.

The American proposition is that the basic rights that it is government's highest duty to protect and strict obligation to respect are not the gifts of kings or presidents, parliaments or congresses--or courts. They are not given to us by any human power; so no merely human power may legitimately transgress them or take them away. It is the duty of human government, rather, to protect and respect them.

Now this is not an affirmation that can be made only by Christians and Jews--heirs of the Biblical tradition of ethical monotheism. Certainly Muslims, Sikhs, Baha'is, and people of other traditions of faith can make it. Even a Deist (in the old-fashioned sense, not the contemporary one) can make it. Jefferson, after all, speaking of slavery, said "I tremble for my country when I consider that God is just, and His justice will not sleep forever." (Jefferson said this despite being a slaveowner--a fact that all college students today know, even if they know nothing else about Jefferson.)

But what about the non-theists?

Non-Theism, Materialism, and Transcendence

Well, there are non-theists and there are non-theists. There are non-theistic traditions (such as some forms of Buddhism) that recognize the spiritual nature of man. Typically, these traditions, though God is not part of the picture, assume the existence of transcendent reality in an economy in which the human person is subject to moral requirements and responsible for his actions. As more-than-merely-material creatures, human beings can have fundamental dignity--even sanctity--and be the subjects of rights and duties.

But things get murkier--quickly--when we consider forms of atheism that reject the transcendent and spiritual altogether, supposing that human beings are random products of meaningless forces being pushed around in a universe governed exclusively by material and efficient causes. In such a universe, human beings cannot truly have freedom of the will or capacities for more than merely instrumental rationality. How such creatures could possess dignity--much less sanctity--and be the bearers of unalienable natural rights is, to say the least, less than clear.

Given the sometimes extreme stresses and strains that inevitably come into the lives of nations as well as individuals, can we confidently say that the conditions of constitutional freedom--and thus freedom itself--would survive where the great mass of citizens had settled into believing that human beings, supposed subjects of inalienable rights, are merely material beings inhabiting a universe of purely material and efficient causality? That, it seems to me, is a proposition that should be indulged only with the very greatest caution.

Robert P. George is the McCormick Professor of Jurisprudence, and the Director of the James Madison Program in American Ideals and Institutions at Princeton University.