How do they know the Unknown Soldiers' nationality?

It is generally said that the Tomb of the Unknowns in Arlington, VA has the bodies of several unknown American soldiers who were never positively identified as the body of any specific person, such as PFC George Jones of Omaha or Lt. Colonel Thomas Haines of Memphis. Given the fact that, by definition, the people interred there cannot be positively identified, how do we know that they are even American? How do we know that the WW2 unknown is not a British soldier of the Black Watch whose uniform was burned away by a flamethrower attack? How do we know that he wasn’t actually a Nazi Stormtrooper who was robbed at gunpoint for his uniform and ID by a French Resistance fighter? Considering the ethnic mix of the US, I’m not sure I would not trust an ethnographer’s ruling that, “We don’t know who he is, but his DNA comes out to be 75% German and 25% Italian, therefore I conclude that he was probably mostly Pennsylvania Dutch but his grandma was an Italian immigrant who settled in Philadelphia.”

I’d guess that the remains of their uniforms would give a pretty strong clue as to who they were fighting for. Even underwear and socks would help.

Yeah, “unknown identity” just means that they couldn’t find the dog tags or name patch. But pretty much any scrap of uniform at all would be enough to identify the country. Now, one can’t rule out that the corpse is from a different country than the uniform, of course, but that seems a silly thing to worry about.

It is likely the bodies were collected from areas known to be occupied by US troops and they were dressed in US uniforms - what there probably was left of them. DNA testing was not invented when the unknowns for WW1 and WW2 were interred. Also, the unknowns were selected from a set of unknown bodies gathered together for the purpose, none of whom could be identified by the means available at the time.

Per Wikipedia, the unknown soldier from the Vietnam War was subsequently identified by DNA testing and his remains removed from the Tombs of the Unknown at Arlington, to another grave site which correctly identified him.

Actually, the unknowns probably could be identified now, if we had a small group of possible candidates. DNA analysis f the remains compared to living relatives of the possibilities would probably identify them fairly conclusively.

But we don’t want to do that!
People would object to opening those graves to collect DNA material, and then to the removal of the body once it was identified. Some people would object to the diminution of the memorial, and some others would object to the cost of the whole project. So it is pretty unlikely to ever happen.

There are no unknown soldiers from modern wars, since Vietnam, and there likely never will be. Now even including Vietnam, with DNA records and such all the bodies have been identified. So this war memorial will probably never grow again.

Would that the actual cemeteries for dead solders would never grow again!

One would also imagine that the human remains of the soldier to be interred as THE unknown soldier for a specific war were carefully chosen for that purpose, i. e. the circumstances of his death made it as certain as possible that the deceased was in fact an American soldier.

As another posted already pointed out this has already been done. Nobody objected. The biggest controversy I can remember is that the family of the identified soldier wanted him to keep the Medal of Honor that is awarded to the Unknown Soldier.

Are you talking about the unknowns from Korea and before? Is it not a matter of “not wanting to do it” so much as it is the logistical nightmare of doing it? I mean, where would you start? They’re “unknown” because, well, we don’t know who the hell they are.

It’s possible from whatever evidence we have (where they were collected from, anything they had on them or their uniform) to determine, very generally, where they fought and who they may have fought with, but #1 I’m certain that all efforts were made to identify them at the time they were ruled to be “unknown,” and #2 even if you could determine a general time and place, say a certain town in Pennsylvania, what then? Are you going to take DNA samples from everyone in town? From everyone who ever had a relative from that town? That could easily be tens of thousands, if not hundreds of thousands, of people, and after 60, 70, 100, or 150 years respectively (Korea, WW2, WW1, Civil War), there may not even be any remaining relatives.

First, you should realize that the whole idea that there was even any point in identifying every dead soldier and burying them in a grave with their name on it is relatively new. It goes back to World War I:

The further back you go in history, the less care there was about the burial of individual soldiers. If they bothered to dig a hole and bury all the dead on the battlefield, it was considered pretty considerate at one point. Then it gradually became more common to bring the bodies back to their home countries and bury them there in mass graves. Then there was increasingly attempts to identify individual soldiers. It was considered sufficient at one point to just say, “Hmm, the uniform is ours, but the identifying marks are gone. Nobody among the survivors on the battlefield recognize him. He’s unknown. Bury him.” The extensive effort now made to identify every single body on a battlefield and return it to his family is quite recent.

All you’d really need to do is take DNA from everyone in that town related to a soldier who was (and presumably still is) MIA.

I think that depends on the specific culture.

I remember learning way back in school of Greek Spartan parents telling their sons aw they go off to battle to return “bearing your shield or borne upon it”. Which would seem to indicate that they expected that each dead soldier would be returned home.

I wonder if it isn’t later that this feeling ended, perhaps with the rise of mass armies and faraway battles, like around the time of Napoleon., I suspect that that’s not what happened to the average dead Spartan soldier. I suspect that the statement was merely the typical hype aimed at encouraging young men to fight their hardest in war. The statement was saying that of course the Spartans will be victorious in battle. They will overcome their enemies so thoroughly that only a few of the Spartan soldiers will die in battle, so it will be a trivial job for the remaining Spartan soldiers to carry the dead Spartan bodies back with them.

If the Spartans were defeated or if they won but only at the cost of most of their men dying in battle, then it would be impossible to carry the dead bodies back to Sparta. The claim of the hype was that the Spartans would slaughter their enemies with few deaths of their own, so it would be easy to bring back the bodies of the few dead soldiers. The point of the hype is that every soldier must give his best effort. A coward would neither survive nor die a heroic death.

That is what I suspect. However, I admit that I am no expert on military history. Is anyone here an expert on it? Does anyone know someone who is an expert on it who can ask them about this?