On late Friday afternoon, with President Bush arriving in Hanoi for the Asia-Pacific Economic Cooperation summit, news broke of a casualty in Iraq. His name was Tung Nguyen, 38, a sergeant first class, and a member of the U.S. Army Special Forces.

Nguyen had died in a firefight in Baghdad on Tuesday. The Army is investigating the events of Nguyen’s death, an inquiry that will look into the possibility of friendly fire. There have been 2,864 fighting men and women killed in Iraq, and a story lies behind each and every one of them. But the arc of Nguyen’s life, which began in Vietnam and ended in Iraq, says as much about sacrifice and what it means to be American as any of them.

He was born the year of the Tet Offensive, the great turning point in Vietnam on two fronts: It was the year the Viet Cong expended the bulk of its resources turning the conflict from an insurgency to a war more directly executed by the North Vietnamese army. It also marked the moment when the American public, surprised by the enemy offensive on Saigon, and elsewhere throughout the country, began to lose heart in the struggle.

Eight months before Nguyen’s birth, in October, Special Forces Company D, headquartered in his hometown of Cantho, fought off an attack. The elite soldiers, the Green Berets, who defended Cantho did so under the Special Forces motto “de oppresso liber,” which is a fancy Latin phrase meaning “to free the oppressed.”

The Special Forces were among the first Americans to fight and die in Vietnam. President Kennedy believed that these unconventional troops could be an important tool in the fight against communism. He visited the Special Warfare Center at Fort Bragg, N.C., in 1961, an institution that took Kennedy’s name after his assassination two years later.

It was a member of the Special Forces, Paul Campbell, a sergeant like Nguyen, who was the first American to hike into the Central Highlands in 1961 and provide medical treatment to the mountain people, the Montagnards. Special Force A-Teams followed suit in the years to come, going into camps throughout Vietnam, shoring up defenses, leading groups of irregular fighters, and dispensing medical care.

The Americans left Vietnam in 1975 and several years thereafter so did Nguyen. The details are still sketchy. Following the fall of Saigon, Nguyen fled Vietnam with relatives, leaving his parents behind. This was the era of the Vietnamese boat people, when thousands of opponents of the communist regime and those seeking a better life made their way to sometimes makeshift boats and left the country. Nguyen ended up in Tracy, Calif., outside of Modesto. He struggled to bring his parents to America and graduated from Tracy High School in 1986.

He was first an infantryman, then a paratrooper, serving in the 101st Airborne Division, and, finally, a Green Beret. A crack shot, foster brother Jim Cracraft told the Modesto Bee, Nguyen’s ambition was to join the military. Recognized as a master marksman, Nguyen became an instructor at the John F. Kennedy Special Warfare Center in 2003 and, later, shipped out to Iraq.

Much more can probably be learned about Nguyen’s service in Iraq. Right now details are scarce. The Army press release states that Nguyen was posthumously awarded the Purple Heart, the Iraq Campaign Medal, the Bronze Star, and the Combat Infantryman Badge, which denotes action under fire and combat with the enemy.

Forty years ago, another Special Forces sergeant, Barry Sadler, had a number one hit song with “The Ballad of the Green Berets.” In his fifth verse, Sadler sang “Back at home a young wife waits, Her Green Beret has met his fate, He has died for those oppressed.” Like the soldier in “The Ballad,” Nguyen had a wife at home, Marcia. She will mourn Nguyen at a private funeral at Fort Bragg tomorrow.

Nguyen, in turn, will not be forgotten. Members of Special Forces alumni chapters have a tradition of paying tribute to their fallen brothers for years to come. In Las Vegas, for example, the members of Chapter 51 gather every month. They commence each meeting reciting the names of those Special Forces soldiers killed that month. The list for November begins with Sergeant First Class William Everheart, killed in 1963, and contains 74 other names, most of them killed in the land of Nguyen’s birth.

No matter what happens with troop levels in Iraq in the coming months, members of the U.S. Army Special Forces will surely be putting themselves in harm’s way throughout the world in the years to come. They will do so selflessly, in the name of the Special Forces motto “de oppresso liber,” to free the oppressed.

Mr. Gitell (www.gitell.com) is a contributing editor of The New York Sun.