“Think not that I am come to send peace on earth,” Christ declares in the Gospel of Matthew. “I came not to send peace, but a sword. For I am come to set a man at variance against his father, and the daughter against her mother, and the daughter in law against her mother in law. And a man’s foes shall be they of his own household.”

The Bible is full of hard sayings like this—too many, too hard, to be entirely exegeted away in historical criticism, or eased with gentler passages in antidote, or shrugged off as the overstatement of prophetic rhetoric. From the Pentateuch to the Prophets, from the Gospels to the Book of Revelation, something there is in both testaments that has no patience for political compromise, or moral casuistry, or conventional prudence, or philosophical judiciousness.

It’s not the only thing in the Bible, of course, but without it, we have no Bible. “A fire is kindled in mine anger,” as Deuteronomy puts it, “and shall burn unto the lowest hell, and shall consume the earth with her increase, and set on fire the foundations of the mountains.”

There is something in America, as well, that has always burned against the world. From Cotton Matther to William Lloyd Garrison, from John Brown to Martin Luther King, there has been here a hunger to speak with lips touched by burning coals, a blessed rage for the apocalyptic lessons taught only by tongues of fire.

A nation formed by political geniuses—masters of compromise, philosophers of prudence, judges of wisdom—we are also a nation with another theme. Something here has, from the beginning, disdained political order and sought not to be brilliant, wise, and learned, but only true, though the heavens fall as a result. “I am come to send fire on the earth,” Christ says in the Gospel of Luke, “and what will I, if it be already kindled?” It’s not the only thing in America, of course, but without it there is no America.

This is a problem for politics. Indeed, it is the root of the theo-political problem that haunts us to this day. Public order in a democracy—the structure of liberalism that needs a people of virtue to maintain itself—seems to require the bulk of citizens to believe in God. But no one ever believed in God for the sake of public order in a democracy. Especially not Americans.

A momentous dilemma results from this. Liberalism needs religion, and needs it in a variety of ways, from the simple genealogy of modernity’s birth out of the spirit of Christendom to the complex reliance of modern times on an enduring set of premodern assumptions and virtues.

But religion doesn’t need liberalism, and the rhetoric of biblical prophecy would burn the world to the ground if a still, small voice demanded it. “God gave Noah the rainbow for a sign,” as the old spiritual put it: “No more water, but the fire next time.” And to reap the benefits it needs, a democracy must allow religion to remain the potential trump, the threatened uncontrollable, the possible authority outside a modern state that longs to have no authority outside itself.

Liberal democracy can be menaced even when the prophet doesn’t return from the wilderness to preach fire and brimstone in the public square. Throughout our history, biblical America has often stood outside political America: the wayfaring stranger far away from the public man, however much the political world echoes with the words of a public God.

And this, too, is a threat—perhaps even a greater threat than a prophet like Garrison proclaiming publicly that a constitution perpetuating slavery is “a covenant with death and an agreement with hell”—for it leaves us with a mass of citizens who suffer the political order merely because they don’t think it important enough either to attack or to defend. “When ye shall see the abomination of desolation, spoken of by Daniel the prophet, standing where it ought not (let him that readeth understand), then let them that be in Judaea flee to the mountains.”

In other words, the Bible may help produce the ethics a modern state needs to assume in its citizens if it is to allow them freedom, but the Bible didn’t start out as the ethics of liberal democracy. It may not even contain an ethics at all, in the sense in which philosophers speak of “ethics.”

Render unto Caesar the things that are Caesar’s, yes. Understand that God has allowed the sword to remain in the hands of the magistrate, indeed. But the day may come when a prophet is told to enter the public square and cast down the nations—just as the day may come when a private man is told, “Take now thy son, thine only son Isaac, whom thou lovest, and get thee into the land of Moriah; and offer him there for a burnt offering.”

And with these possibilities, ethics in any philosophical sense has disappeared. Whatever political benefits a state gains from biblical religion, how can a liberal democracy allow even the chance of such things? They are immoral on their face—or amoral, or supermoral, or extramoral, or use what word you will: They are outside the capacity of any ethical political order to allow.

Except that if the political order doesn’t admit their possibility, then the political benefits of religion cannot be held, and democracy itself decays. “Whatever may be conceded to the influence of refined education on minds of peculiar structure,” Washington famously warned in his Farewell Address, “reason and experience both forbid us to expect that national morality can prevail in exclusion of religious principle.”

The United States as it naturally wants to be—what we might call the platonic ideal of America—contains a tension we must be careful not to resolve. From its founding, the nation has always been something like a school of Enlightenment rationalists aswim in an ocean of Christian faith. And how shall the fish hate the water wherein they live? Or the water hate the fish?

Genuine secularism—of the kind that would lead, for example, to French laïcité and the complete banning of religion from public life—was never really what the American theo-political tension was about. In its modern form, that secularism was an import from nineteenth-century France and Germany, mostly, based on a notion of intellectuals’ vast superiority to vulgar religious belief and a reading of history as proving that battles among Christian sects are the greatest danger to political order.

None of America’s founders had a comparable disdain for religious belief, and American history contains nothing analogous to the European wars over Protestantism. Both sides “read the same Bible, and pray to the same God, and each invokes his aid against the other,” Lincoln said of America’s most costly division, and as the Civil War went on, his cadences and his thought grew more biblical, not less, as though only the language of the prophets were sufficient to express the horror and the necessity of the conflict: “Fondly do we hope—fervently do we pray—that this mighty scourge of war may speedily pass away. Yet, if God wills that it continue until all the wealth piled by the bondsman’s two hundred and fifty years of unrequited toil shall be sunk, and until every drop of blood drawn by the lash shall be paid by another drawn with the sword, as was said three thousand years ago, so still it must be said, ‘The judgments of the Lord are true and righteous altogether.’”

No, the question in America was always how to reap the benefit from biblical religion while minimizing the dangers of extra-political authority and a set of citizens called by their deepest beliefs away from any desire to help defend the political order. Part of the American situation in the eighteenth century was historical accident, or perhaps—as Madison put it in an extraordinary letter—God’s direct providence that preserved the New World undiscovered by Europeans until they were ready to try this experiment in freedom. But, whether the participants willed it or not, the American Revolution occurred in a Christian moment, formed most immediately by the progress of religion from the Puritans to the Great Awakening.

That gave the Founding Fathers massive advantages. But the overwhelming Christian faith of America also presented the Founders with terrible disadvantages, for the Bible cannot be entirely tamed to any public purpose or ethical reading. “Have ye not known? have ye not heard? hath it not been told you from the beginning? have ye not understood from the foundations of the earth? It is He that sitteth upon the circle of the earth, and the inhabitants thereof are as grasshoppers; that stretcheth out the heavens as a curtain, and spreadeth them out as a tent to dwell in: That bringeth the princes to nothing; He maketh the judges of the earth as vanity.”

The tense and awkward solution of the Constitution derives, I think, from an awareness that the benefits and the dangers have the same root. “Biblical America” is the oxymoron that defines us, the contradiction that maintains us. If we lose either our extra-public religion or our Enlightenment use of public religion—if we break the delicately poised balance between the force of Christianity and the drive of modernity, if either side in this tension ever entirely vanquishes the other—the United States will cease to be much of anything at all.

Even while the mass mind’s mindless cant clatters all around us, there is much that must be celebrated: the worldly wisdom of a broad and democratic spirit, the reasonable discourse of reasonable men seeking reasonable compromises. The platonic ideal of the United States must have these things; America is not America without them. But America is also not America unless, underneath it all, a small voice whispers that the nations are as a drop in the bucket and are counted as the small dust on the balance. America is a triumph of political philosophy because it is not entirely political—because it also hears, even in these latter days, the murmur, “I am come to send fire on the earth; and what will I, if it be already kindled?”

Joseph Bottum is editor of First Things. This essay is his opening remarks for the 2010 New Mexico Biblical World View Conference, to be held this week in Albuquerque.