We have no idea what his significance is, because the historians in question haven't even figured out what he did at Los Alamos. Which to me makes the whole thing feel a little premature I have to admit.

I have no idea if the difficulty is classification or what. Presumably Seborer's FBI file goes into some of this stuff (and it must have a photo, because the Greenglass FBI file says they showed the photo of Oscar Seborer to Ruth Greenglass for identification — she didn't know him).

So there are huge unknowns here, to the degree that it's not really possible to make any real useful sense out of this. I think the NYT article vastly overstates the "meaning" of this — not that it couldn't have meaning, but the unknowns are too large to know.

As for what he likely knew: it appears that he was a member of the Special Engineering Detachment. That means he is an engineer who would be under military chain of command (and lived in bunks, etc.), and would be basically assigned to help scientists at the lab. The SED were mostly used to perform tasks and experiments; they weren't treated like actual scientists, but as sort of lowly technicians. Greenglass was a SED and his job was mostly to cast explosives. From that he was able to piece together a crude idea of how the implosion bomb worked, and learn a few other isolated classified concepts (like "levitation," a weapon design technique they were exploring during the war, but only used in the postwar).

If Seborer's exposure was anything similar to Greenglass (not in the specific subject matter, but the limitations of knowing), then he wouldn't have likely been as significant as someone like Fuchs (who was deeply knowledgable of many different areas of weapons design and even fissile material production).

But again, we don't really know what he did. The above is just speculation based on what little is out there.

My biggest problems with the NYT article are:

• "the director of Cold War studies at Harvard, said the study cast new light on “how widespread espionage was in the Manhattan Project.”" — It doesn't, really. We already knew that there were maybe a dozen spies in the Manhattan Project (with only a few being "well-placed"). Adding another Greenglass-like figure doesn't change much.

• "It helps to reframe a long debate, he added, on the relative importance of American spies and Russian scientists to Moscow’s 1949 atomic breakthrough." — It doesn't at all change or even inform this debate. To change that debate you'd at the least need to know what Seborer passed on, and you'd need to know how it was used by the Soviets. We do know how the Soviets used intelligence information — they didn't use it very directly, because they didn't trust it. It seems unlikely that learning what Seborer passed on would change any of this understanding.

• "news of Mr. Seborer’s spying, combined with the known atomic thefts, “makes clear that Soviet weapon scientists were receiving a great deal of valuable information. Espionage, by pointing them in the right direction and avoiding false leads, helped them a lot more than they were willing to acknowledge.”" — Again, this is not about what information was received, but how it was used. We have great amounts of information on how espionage information was used (because the Russians opened their archives in the late 1990s). They didn't use it efficiently. They in fact investigated the false leads as well. The Soviets were unwilling to acknowledge this at the time, but the Russian Federation has gone to great lengths to acknowledge the contributions of the intelligence services to the development of the atomic bomb, and clarify exactly what those contributions were and weren't.

• "Declassified files on the Solo operation bristle with fascinating hints of Mr. Seborer’s espionage for the Soviets but offer few details, according to the study. It quotes another member of the “Relative’s Group” as telling an informant, “He handed over to them the formula for the ‘A’ bomb.”" — There is no "formula for the A-bomb" and anybody who said that has basically indicated they do not understand how nuclear weapons work at all. It is not that kind of bomb.

• "he hoped that new files released in the future under FOIA to the scholars would “fill in a whole bunch of gaps.” The F.B.I., he added, “takes its own good time in these matters.”" — This is a minor nitpick, but the FBI is easily the fastest and most responsible agency I've dealt with for FOIA requests. (I have filed dozens of FBI file requests.) I would expect them to take no more than a year or so. Which is fast by FOIA standards.

• "K.G.B." — Seborer did not spy for the KGB, because the KGB did not exist until 1954. I expect the NYT means the NKVD. This is a nitpick but sort of a rookie mistake.

Anyway — I don't want to be a killjoy and nitpicker (or do I? sometimes I wonder), but the importance of this seems vastly overstated given the unknowns. It's neat to have another line of research opened up and I look forward to seeing what comes out of it in the future, however. I do not blame the scholars for perhaps overstating the importance of their work to a journalist (we've all been there, I suspect).