The sudden spike in American casualties in Iraq is unlikely to quickly turn public opinion against the war, several experts said yesterday.

Although in recent years Americans have become unaccustomed to significant numbers of American troops dying in combat, support is likely to remain strong if U.S. leadership stays committed and the war is perceived as being waged competently, the experts said.

Since some 58,000 Americans were killed in Vietnam, the U.S. military has rarely experienced a significant number of casualties. The biggest loss of life occurred in 1983, when a terrorist bombing of a U.S. military barracks in Beirut, Lebanon, killed 241 soldiers. Nineteen Americans were killed in the 1983 invasion of Grenada; 23 were killed in the 1989-90 invasion of Panama; 29 were killed in Somalia in 1992-93; 147 were killed in the last Iraq war; and about 25 Americans were killed in Afghanistan.

An estimated 16 Americans were killed and at least five were taken prisoner yesterday in two clashes that resulted in the largest number of U.S. casualties of the four-day-old war. Yesterday, the Pentagon identified as Army Capt. Christopher Scott Seifert of Easton, Pa., the soldier who was killed in the grenade attack at Camp Pennsylvania in Kuwait; a U.S. soldier, Sgt. Asan Akbar, is in custody, suspected of throwing the grenades.

"A few years ago, it was conventional wisdom that the American people would tolerate no casualties in war," said James Burk, a sociologist at Texas A&M University in College Station. "My own research and the research of others has pretty well demonstrated that the American public is tolerant of casualties as long as the casualties are incurred in pursuit of a mission that they think is reasonable. The public will be patient as long as the casualties don't seem to be the result of carelessness or incompetence."

The public did not support, for example, President Jimmy Carter's botched attempt to rescue the hostages in Iran because it was seen as ill-conceived and halfhearted, Burk said.

The Bush administration clearly understands that the American people are more "defeat phobic than casualty phobic," said Peter D. Feaver, associate professor of political science at Duke University.

"Almost every time they mention casualties, they will close it out by saying, 'This is not going to stop us from prevailing.' That is sending a very clear signal to the American public that, 'We're not going to lose. These people will not die in vain,' " Feaver said. That understanding was clear yesterday in how U.S. officials reacted to the release of a graphic video of dead and wounded soldiers.

"That video could have been seen as rattling public opinion. But instead the administration was very careful to say instead that this proves the point of why we're there in the first place: 'They can't be trusted,' " Feaver said.

That was in stark contrast to how the Clinton administration reacted to a video of American soldiers being dragged through the streets of Mogadishu, Somalia, in 1983 following the "Black Hawk Down" incident in which 18 soldiers died, Feaver said.

"If the Clinton administration has done what this administration is doing, that video may have stiffened the resolve," Feaver said.

In fact, the immediate public reaction to that incident was anger, according to Steven Kull, director of the program on international policy attitudes at the University of Maryland.

"The majority of Americans did not respond by wanting to pull out our troops. They responded by wanting to beef them up," Kull said.

Similarly, casualties in Iraq could harden U.S. public opinion against Iraq, several experts said.

"We should expect American tolerance of casualties to increase as part of their anger with the Iraqis," Burk said.

And if the military sees public support rise in the face of casualties, it might counter the military's squeamishness to casualties, which is one of the lingering effects of the trauma of the Vietnam War, Feaver said.

"The American military has been criticized for being excessively concerned with protecting American soldiers' lives to the point where some have charged the military was risking its effectiveness," he said. "This is sending the signal that says, 'Hey, we're not going to panic every time a soldier dies,' which is in contrast to the Clinton White House obsession with casualties."

But support could begin to erode if criticism of the war begins to intensify, either internationally or in Congress, Burk and others said.

Another factor that could reverse public support would be large numbers of civilian casualties. "The administration has taken great care to minimize civilian casualties. But should that policy fail, and we begin to see the killing of a lot of Iraqi citizens, I think opposition would grow," Burk said.

Charles Moskos, a sociologist at Northwestern University, said support could start to dissipate quickly unless the nation's elite are also sending their children to war.

"The country will not accept long-term casualties unless the elite or the leadership is willing to put their own children in the line," Moskos said. "National interest is defined by, 'Are the leaders willing to die for it?' "

Kull noted that support could erode if the war does not proceed well, the nation begins to suffer retaliatory terrorist attacks or faces continued criticism internationally.

"Support is not robust. A lot of people are saying that they are behind it because they want to support the president. That creates a precarious situation," Krull said. "If there were continuing casualties, and the military operation was perceived as being bogged down, and criticism continued, then the underlying doubts about the operation would start surfacing. But I don't think we're near that right now."

Two Marines, not shown, whose armored personnel carrier was hit by a rocket-propelled grenade yesterday, receive medical care.