As the smoke of battle cleared over Antietam in 1862, two noncombatants picked their way through the human carnage. They were armed not with guns, but with new devices of profound importance for the future of war: cameras.

They had been sent to Maryland by Matthew Brady, at whose New York gallery there subsequently appeared an exhibit, "The Dead of Antietam." A New York Times reporter wrote: "The dead of the battlefield come up to us very rarely, even in dreams. ... Mr. Brady has done something to bring home to us the terrible reality and earnestness of war. If he has not brought the bodies and laid them in our dooryards and along our streets, he has done something very like it."

A century later, in Indochina in the 1960s, cameras would change the relationship between war and the home front, and hence would limit the ability of democracies to have recourse to force. Saddam Hussein may have this in mind when he says, "America is not a society that can stand 10,000 casualties in one battle." America did stand it at Antietam. But that was before the graphic revolution in communication.

That revolution produced, in time, television, and a new tension between a traditional instrument of statecraft, war, and the foundation of democratic government, opinion. But that tension was a long time in coming.

Robert Hughes, the art critic and historian, writes about the cynicism in the aftermath of The Great War (as it was known to a generation quaintly confident that the future had nothing worse in store). Hughes says people knew they had been lied to, not least by journalism: "A compliant and self-censoring press had seen to it that very little of the reality of war, not even a photo of a corpse, found its way into any French, German or British newspaper."

In 1943 Life magazine created controversy, and a new era in journalism (and in international relations), by publishing a photograph of three dead Americans on the beaches of New Guinea. We were not yet a wired nation during the Korean War, so Vietnam was the first "living-room war." All future wars will be.

Because of television, which makes war's horrors instantaneously and universally immediate, democratic leaders must take extraordinary care to prepare civilians for the facts of combat. That is a political reason (there also is a constitutional reason) why Congress should convene immediately to begin either protecting Americans from, or preparing them for, the eruption of slaughter in their living rooms.

But suppose there is no bloodshed. Suppose economic sanctions are given time to work, and do. And suppose success is achieved not by tidy technological pressure -- not just by denial of spare parts for Saddam's military machine -- but by the most basic deprivation: of food.

Last week Iraq claimed, almost certainly falsely, that the sanctions are killing babies. Iraq produced pictures showing a malnourished baby with a swollen belly, purportedly a victim of the sanctions.

Let us be cleareyed about our hopes that the sanctions will make war unnecessary: suffering children are part of our objective.

In 1932 the Western world was still reeling from The Great War and was looking for alternatives to violence. (The next year Hitler came to power, and two weeks later students of the Oxford Union voted for a resolution never to fight for king and country.) In 1932 a Twentieth Century Fund report, the authors of which included John Foster Dulles, assessed food embargoes against nations that import (as Iraq does) significant amounts of foods:

"{Food embargoes} are not persuasive measures, but the most savage of war measures. They are particularly difficult to uphold on merely moral grounds, since they bear more heavily on the civilian population than on the army, and more heavily on women and children then on the men. For effectiveness, and for moral standing, a really successful food embargo ranks well in advance of torpedoing hospital ships and is somewhere near the class of gassing maternity hospitals."

Even allowing for hyperbole, the point is germane. Have America's leaders prepared the public for the sight of the success of sanctions: pictures at dinner time, in living rooms, of babies' swollen bellies?

So far the primary role of television in the crisis has been to tell the story of our plucky military men and women making do in the desert. On what may be the eve of war, while huge numbers of hospital beds are ready for casualties, television chat-shows punctuate their segments with cheery snippets of tape showing soldiers saying "Hi, Mom!" Are Americans ready for the real thing?

It cannot be proven, but it is believable that today's public wariness about war in the Gulf is, at least in small part, a result of recent exposure to black-and-white war photographs 125 years old -- those from Antietam and elsewhere that were used in the PBS series on the Civil War.

Saddam, whose defensive deployments are designed to maximize U.S. casualties quickly, knows the crucial question: What can Americans stand?