Saw this claim and it made me pretty curious:
Didn't this happen where America ordered scientists to stop making public, research papers on nuclear technology. The Soviets spotted the absence, and immediately steamed into nuclear research.
This is discussed in detail in The Making of the Atomic Bomb by Richard Rhodes. In the late 30s, almost all the atomic scientists realized that a war was coming, and that their work would enable the building of a bomb, and they voluntarily stopped publishing. Almost all, that is, except Jean and Irene Curie (daughter and son-in-law of Marie Curie) who were naively publishing very dangerous stuff right until war was declared. Apparently it never dawned on them to ask why all of their colleagues suddenly stopped publishing.
Not sure if that last sentence was tongue-in-cheek, but I'm also curious if there was any reasoning behind their decision to keep publishing (should the underlying claim of normalized self-censorship be true).
It's hard to imagine such a large proportion of the scientific community keeping their lips that uniformly sealed over something so valuable and prestigious, just for the virtue of it -- especially when the actual danger had yet to manifest.
There's some confusion there, but the reality of it is this. In 1939, after the discovery of fission, Leo Szilard attempted to organize a self-censorship campaign by physicists who he knew might be working on the possibility of nuclear fission chain reactions. He was able to get a number of very prominent physicists and journals in several countries to agree, including the Physical Review, Enrico Fermi, Niels Bohr, PMS Blackett, and several others. He did this out of fear of the Germans becoming hip to the possibility of chain reactions. (They knew about fission, as they discovered it; the question was whether fission produced secondary neutrons, which would make chain reactions possible, which would likely make reactors and possibly atomic bombs possible.)
He then attempted to get Frédéric Joliot-Curie and his team in Paris to sign on to it. Joliot thought it was a bad idea to self-censor — he thought it wouldn't stop the Germans, that it was contrary to how science worked, and he feared that he would lose priority. (Joliot and his wife knew very well how close the game was in scientific priority in nuclear physics. They had both narrowly missed out on several crucial discoveries by mere days. Irene had herself narrowly missed out discovering fission.)
Joliot doesn't seem to have been totally committed to defying it, though, until an article written by an American physicist who did not know about the self-censorship campaign made it seem like the Americans weren't even going to be consistent on this, and at that point Joliot told Szilard (through an intermediary) that he wasn't going to participate and immediately moved to publish an article on secondary neutrons. After that, many of the Americans who had held back also published.
You can read about this episode in chapter 1 of my book on the history of nuclear secrecy in the United States; it is also well-told in an article by Spencer Weart called "Scientists with a secret."
I would say that this was not a "normalized" thing at all. It was not a huge list of physicists who did this, and many of them had to be very passionately convinced (Fermi was skeptical of the whole thing). The scheme only worked as well as it did because a) many of them were refugees against the Nazis and uniquely feared them, and b) because the journals agreed to mark when the articles were received, so priority could be somewhat preserved. And it only lasted a few months at most. And Frédéric knew about the campaign; he deliberately flouted it. (And Irene was not involved.)
There is a separate story about a Soviet physicist spotting the absence of publication from a later period — this is the famous Georgii Flërov story — but that is once official (government) secrecy was put in place (a later development), not the self-censorship campaign. The official government secrecy was initially built upon the infrastructure first created during the self-censorship campaign, as an aside. Again, chapter 1 in my book goes over all of this in great detail.