Every physicist knows how nuclear weapons work. However, where our weapons are deployed, our level of readiness to use them, and what we know about other countries’ weapons and deployments would not be common knowledge. Any person with a completed undergraduate and/or graduate education in physics knows how they work. The details of quantum mechanics, radiation, nuclear fission, fusion, electronics and so forth are in our textbooks. These things are well known to us. Many of us have a good idea of the basic engineering behind nuclear weapons. We know what materials are needed, and what type of precautions are needed to work with them. This is the reason only countries with a certain degree of engineering and industrial prowess can even pursue a credible program. Any country able to build its own reactor can do it at the turn of a screw.

The truth is secrecy of the basic physics and engineering is not what prevents proliferation. The sheer expense and difficulty of accomplishing the engineering of nuclear weapons is. To handle radioactive materials safely is no easy feat. To engineer with them is even harder. Everyone who wants nukes knows what needs to be done. The trick is having the industrial capacity to do it, and an economy that can finance it.

That said there are some real nuclear secrets aside from the mere operation and construction of a nuclear bomb.

• Where are they stored or deployed?

• What and how do we know about other nations storage and deployments of nuclear weapons?

• The details of negotiations around nuclear non-proliferation and arms limitations.

• The capabilities of our weapons platforms (as in ships, planes, missiles, and subs) for delivery

• Our knowledge of other countries’ weapons systems.

• The capabilities of our surveillance systems and what we know of our potential adversaries.

• Names of sources on the nuclear weapons of other countries.

In short, information former president Trump may have had would not be scientific points of how these weapons work. It would be a fool’s errand to try to keep that a secret since, even as soon as we used these weapons on Japan their basic construction was known to other scientist. However, knowledge of where our nukes are, how they are deployed, and how we might plan to use them would be a crucial secret to keep.

As a curious person a question in my mind is why were these very secret documents left with Donald Trump for so long?

The most highly classified documents would have only one extant hard copy. How would it not be obvious if that copy wasn’t in stock at the one location it is supposed to be kept at? The key question is are these documents which were marked as Top Secret and Compartmentalized mere copies of documents which exist now in declassified form and these older copies simply had not be remarked or perhaps redacted? Any normal person who had these, even if they had a job which gave them clearance to see them, and had some extraordinary permission to take them home at one point in time (as Trump did being the president of the United States) would need a very good lawyer.