WASHINGTON — Every war or disaster contains moments that become defining images: a napalmed girl or a gun to the head in Vietnam, the body of a U.S. soldier dragged through a Somalian street.
It is not clear whether the 80 seconds of video Wednesday showing images of charred American bodies being beaten and dangled from the steelwork of a bridge over the Euphrates River will come to define the war in Iraq.
But once again, broadcasters and news executives were torn between a question of taste and the demand to give viewers and readers information that could affect the course of history.
"War is a horrible thing. It is about killing," ABC News "Nightline" Executive Producer Leroy Sievers said in an unusual message to the program's e-mail subscribers discussing the issues posed by Wednesday's killings. "If we try to avoid showing pictures of bodies, if we make it too clean, then maybe we make it too easy to go to war again."
On "Nightline," images were shown of the bodies hanging from the bridge, but several other, even more graphic close-up images were omitted.
The video from Fallouja on Wednesday was so graphic, so horrific, that several U.S. television networks held back showing it, wrestling through the day with just how much to use on their news programs.
Some TV and newspaper websites, including that of the Los Angeles Times, offered video from Associated Press of the grisly killings of four American contractors in Iraq, warning visitors that it contained "graphic, violent images."
The events Wednesday -- and the responses they provoked -- were bluntly reminiscent of the downing of a Black Hawk helicopter in Somalia in 1993, followed by upsetting images of a slain American soldier being dragged through the streets of Mogadishu, the capital.
That incident eventually led to a change in U.S. policy. It was not clear Wednesday whether the graphic video of the deaths of American civilians would alter public opinion or the prosecution of the war in Iraq. But that possibility confronted policymakers and news executives across the country.
White House Press Secretary Scott McClellan said that with such attacks, "the enemies of freedom, the enemies of the Iraqi people, are trying to shake our will, but they cannot. We will not be intimidated."
But recognizing the effect that such images have had in the past, he urged caution and told reporters, "I hope everybody acts responsibly in their coverage."
The decisions could have a political impact. While showing the images could erode support for the war, not showing them could have an opposite effect.
Tom Rosenstiel, director of the Washington-based Project for Excellence in Journalism, said that networks' "sanitization of war may have helped the administration prosecute the war" a year ago.
During the height of the war, few pictures of slain American soldiers were shown and news photographers were not allowed at places where they could shoot images of coffins being shipped home.
The pictures from Wednesday's attack, Rosenstiel said, could anger viewers or "engender disenchantment about the war."
The administration should be acutely concerned about the impact of images of atrocity against Americans, said Gordon Adams, a former Clinton administration official.
"Pictures like this are megaphones," Adams said. "They are megaphones about being an American and being in Iraq. The security situation in Iraq has not been solved. The policy has ended up making targets of Americans, and this brings that home."
Mark Gearan, director of communications in the Clinton White House at the time of the Black Hawk tragedy, recalled Wednesday how that episode forced a change in policy.
"It was among the darkest days that the president had, because of the sense of responsibility of having involved U.S. forces and the horror of what happened," said Gearan, president of Hobart and William Smith Colleges in Geneva, N.Y.
Soon after, the United States abandoned its military mission in Somalia.
During the Vietnam War, Associated Press photographs of a Viet Cong guerrilla being executed on a Saigon street and of a naked girl burned by napalm became two of the lasting images of that war.
But with a generation of experience, news executives Wednesday found the decision-making no easier.
Los Angeles Times Editor John S. Carroll said that after considerable debate, "we decided not to use one of the grotesque photographs on Page 1. Instead, we chose to convey the nature of the event by means of headlines and a photo that is not so distressing.
"We also decided to run one of the many photos of the bodies inside the paper," he said. This, Carroll added, gave readers a choice about how graphic a portrayal they would see.
Initially, several networks decided, in the words of a Fox News Channel spokesman, that the video was "too graphic to show on television." But as the day wore on, some began using some of the more graphic images, even showing the blackened, barely recognizable bodies hanging from the bridge.