In the days before the Civil War, U.S. service members who died in battle usually remained nameless in mass graves if they were buried at all.
But over time, Americans became relentless in demanding that all the troops come home to their families dead or alive.
It has never been easy. In past wars, medics depended on dog tags or names embroidered on shirts, but those methods don't guarantee an absolute match. Current policy demands two pieces of scientific evidence DNA on its own does not yet suffice.
Still, beyond the deceased service members identified every week in Iraq and Afghanistan, a team of scientists ends the sometimes decades-long searches of about two families a week by matching a name to the remains of a veteran lost in a distant war long ago.
"Resolved: Advances in Forensic Identification of U.S. War Dead," a new exhibit at the National Museum of Health and Medicine, tells the fascinating tale of how the identification process has progressed since the Civil War.
"This exhibit is about how this nation has a commitment to identify its service members like no other nation," said Franklin Damann, anatomy department curator for the museum, on the grounds of Walter Reed Army Medical Center in Washington, D.C. Everything in the exhibit came from the museum's collection.
The exhibit contains a series of stations for the various sciences involved in identifying remains, such as pathology and anthropology. The stations wrap in a circle around a center display containing a flag-draped coffin. Photos of scientists at work cover the walls.
"This stuff wasn't born overnight when ‘CSI' showed up," joked Damann, referring to the top-rated television show.
He told the story of a Civil War soldier who saw a dying comrade on the battlefield. The soldier handed the man his canteen with his name on it and continued on his way. His was the name under which the dead soldier was buried.
The soldier "would go back and visit that grave every year," Damann said.
In those days, there was no knock on the door from a notification officer to let a family know a service member had fallen in battle, so Clara Barton, the founder of the American Red Cross, took it upon herself to publish lists of the dead, write to family members and act as a go-between for the services and the families.
"Who knows why she did it, but she felt the need to help," Damann said. "That's what's interesting to me: What's the lineage? What's the link to what we do today?"
During the Spanish-American War, a chaplain suggested a possible piece of physical evidence: identification discs, an early form of dog tags.
"Service members would buy them from a Harper's Weekly ad for a dollar or get them from a local jeweler," Damann explained.
They also would pin their names to their shirts, and, in later years, tattoo their Social Security numbers on their chests.
"That's certainly not a DoD directive," Damann said with a grin.
The exhibit includes rings, wallets and lighters left along with the men strewn across battlefields, and Damann said all of these objects still act as clues to identifying remains. A small uniform button found in North Korea sits next to a larger one. The buttons on U.S. overcoats are bigger than those on fatigues.
"That gives you a sense of the season of death," Damann said. "You can exclude those who went missing in the summer."
Scientific evidence to identify deceased troops was first used during the Revolutionary War but generations passed before it was used regularly. Maj. Gen. Joseph Warren died in 1775 at the Battle of Bunker Hill when a musket ball hit him in the head. The British buried him in a mass grave with other Americans, but his family wanted him to have his own marker and funeral.
Fortunately, Paul Revere happened to be a dentist and had created a dental bridge for Warren. Revere went out on the dig to search for Warren's body and found it.
"‘That's the dental work I did for him,'" Damann quoted Revere as saying.
Revere's dental tools also are part of the exhibit.
The services did not begin using professional dentists to identify remains until the 1970s.
The identification task began in earnest after World War II with the "Return of the Dead" program. In the 1950s, scientists worked to use bones to identify ages and body statures, as well as to collect data to prevent future deaths. For example, they looked at the injuries sustained on the remains of a service member who was wearing a flak jacket to develop better body armor.
The "Return of the Dead" program eventually became the Pentagon's Joint POW/MIA Accounting Command Central Identification Laboratory.
Damann used to be a researcher at the Hawaii-based lab. He flew all over the world to identify remains from as far back as World War I.
Before scientific identification ever begins, scientists must figure out who they think the person might be otherwise, that's a lot of dental records to sift through.
The FBI also works with the military to look for fingerprint matches, but it's not like they just pop a fingerprint into a database and wait for its identification, Damann said. The agents have to physically match several loops and curves on the two prints, and that takes time.
"You have to have that tentative name association," he said.
Since the 1991 Persian Gulf War, researchers have used mitochondrial DNA as an identifier, but 7 percent of white Americans have the same mitochondrial DNA which means it can narrow things down, but isn't exact.
"It'd be like flipping through and finding ‘Smith' in the phone book," Damann said. "It's considered circumstantial evidence."
He said scientists are still working out the possibilities of nuclear DNA as an identifier.
In the meantime, researchers still pore over dental records, blood work and fingerprints. In some cases, if there's a "before" picture, they can use an X-ray of the frontal sinus pattern, which is unique to each individual.
"To me, it's pretty fascinating the amount of detail used today compared to the guy with the canteen," Damann said.
Museum admission is free; the display is open to the public from 10 a.m. to 5:30 p.m. every day except Christmas.