TO BE IN Rome is to stand, as it were, before a canyon wall on which the tell-tale marks were made by human hands instead of wind, sun, and rain. The primordial world lives in the ruined Forum, the stripped-to-the-brick facades of temples and theaters, the surviving arches of long-gone aqueducts and imperial palaces.
The legacy of that civilization is a structure of thinking that informs the very words on this page, which attempt to do for ideas what lightning rods do for electricity in the sky. Polarities between republic and empire, beauty and decay, order and tyranny, expression and silence -- these are the tensions which found balance in ancient Rome and uphold still the pillar of culture.
In the post-Constantinian Rome of Christianity, holiness found its match in power, and the match is not over. Its archaeology is in the street. Basilicas began as palaces and became cathedrals without dropping an arch. Emperors became popes and, as they say here, vice versa. The monumental tombs make the point. Yet the message of love found its way into stone as well. Try dismissing belief in Rome's new gospel in the presence of Bernini's ''Saint Teresa in Ecstasy." Nor has any critic of religion ever surpassed the humanist fervor of Michelangelo's ''Last Judgment" -- in the stern presence of which the newest pope was chosen.
In Rome, that is, the corruptions of all that is meant by ''church" are obvious. But the grace undefeated by those corruptions is magnificent, too. Indeed, what is the Renaissance but the moment when corruption itself became the occasion of grace, when the fully human emerged at last from the translucent shell of the will to be divine? The world we know and love came next.
Rome may be the ultimate display of memory, but it is also the world capital of style. Sleek-suited men, supremely composed women, designer cars, the burnished leather of shoes and bags, the front edge of personal invention -- modernity congratulates itself here. The future is as palpable in the people as the past is in the stone. Because the contrast between the present and what precedes it is so dramatic, every trip to Rome requires a reassessment of impression. But such reassessment is precisely the endless work of history. The past is not dead, as Faulkner said; it isn't even past. Memory, therefore, is more about today than yesterday, which is why we visit the so-called foreign country of the past every chance we get.
School children learn to think this way by reading Caesar, and then, perhaps, by learning of Luther. Across millennia, the lesson is absolute. The educational value of glorious Rome is that it fell, and fell again. And each time that happened, out from the ruins crawled the people who had borne the full weight of the imperial structure -- the ones who had actually paved the famous roads, and quarried the infinite supply of marble, and heaped coals on the fires that cut the chill of palace floors; the ones who had faced the inquisitors, questioned orthodoxy, chosen conscience over obedience.
From politics to religion to the new globalism of style, the history of empire is told here as much from the point of view of those who suffer it as those who build it. In Rome, it is impossible any longer to imagine that imperial ambition is simply benign, which is why, perhaps, Americans should visit this city. The educational value of tourism is to see that Rome, having fallen and fallen again, lives on with fallenness as the ground of a more humble glory. A more human one.
What must strike the eye of an American in Rome today, even more than the relics of the layered past, are the new scrawls of enraged graffiti artists. ''No war!" appears on the remnant stone. And ''No war!" appears across the backs of buses, on poster boards, on tacked-up plywood. That the words are English makes the point. In this first home of the new world order, the burdens of idealized violence are all too real.
Across the canyon walls of stripped brick and broken columns, connoisseurs of history declaim with spray paint, ''Stop the war on Iraq!" To the American eye, the word ''on" leaps out of that slogan. Wasn't it in Latin class that subtleties of the preposition first showed themselves? In the United States, George Bush's war is defined as ''in" Iraq, but in Rome, as always, the harsher truth of the imperial impulse is clear.
James Carroll's column appears regularly in the Globe.