Inspired by the thread about photocopies and classified documents-when an agency seizes officially classified documents in a case like Trump’s would they also seize any handwritten notes, journals, or diaries written by the suspect to see if they any classified information in them?
And are they legally considered classified material if they do?
Generally it depends on the context of the document. If he made a cheat of computer launch instructions for nuclear missle launchs then yes, it would be classified and very likely a violation of the Espionage Act for copying classified information.
If it is just a list of people he didn’t like then it is a Presidential record that belongs to the national archieves. Unless he made an agreement to keep it as a personal communication. Which should be a common request.
From the news discussions - it’s the facts, the content, that is classified, not the piece of paper or computer file. Thus, you can be charged for having, or failing to keep safe, any classified documents, you can also be charged for disclosing their contents.
So yes, anything that contains data that came from classified materials is an official secret and must be handled in the appropriate manner only by authorized people. The stamp on the paper is just a notification of the data’ sensitivity.
So yes, not all presidential documents are classified.
The “Executive privilege” is a separate thing. The president and his close advisers are entitled to kick around ideas and discuss options (and write them down) without the risk that some congressional committee gets to see and hear all the details. (“You actually considered bulldozing that area of the city???” “You asked what was needed to bomb Greenland?” “what would happen if we just declared Universal Health care? Can we do it?”)They are private, and the advisors don’t have to talk about his discussion or hand over documents and minutes. Otherwise nobody could speak their mind when developing policy.
I need to make clear that I am not an expert in Government classification. Just a long time employee and contractor for the Federal Government who held Government clearances and received Government user training on the subject. First and foremost, note there are two classification processes. The first is the far more common national security act of 1947 process which delegates the authority to the President. The second is based on the Atomic Energy Act of 1954 and is a different process that doesn’t give the President so much leeway. The national security classification process, as it was explained to me many years ago, requires anyone working for the Government who might generate or become aware of information that might meet the definition of classified information to a) mark the information as classified and treat it as such, and b) bring the document to the attention of a Government classifying officer who will confirm or (rarely) decline to classify the information. Note that how the information is recorded is irrelevant. Pictures, recordings, meeting notes, blackboards, computer disks, etc have all been classified based on the contents.
Note the crucial first step: the information must be marked. Once marked it is by definition classified until declassified. And the marking isn’t optional. Anyone with a “need to know” is supposed to know enough the mark the document first and confirm later. And the classification markings can’t be lightly removed. No one can read a classified document and say, I want to use that in my new novel and simply repeat it without the markings. Removing the markings, thereby making it unclassified, is a process. With regulations.
One can immediately see the core weakness of the process. If one hears or creates information that should be classified (or is classified somewhere) but for whatever reason the individual isn’t aware of the classified nature of the information, say if you are a busy Secretary of State and receive an email, storing that unmarked information isn’t a crime. It is a failure to do one’s job if the person should have known and people have lost their careers due to that failure, but it can’t be a crime. Being dumb is usually not enough to be charged. Mores the pity. But if the document arrives with classification markings, those can’t just be ignored and a copy made. If repeating the information is inadvertent, then the Government frequently just pulls the clearance and ends that person’s career. I have seen that happen. But if there is evidence that the person was knowingly leaking classified information, then the hammer can fall big time.
The warrant is shown here in its entirety.
One clause reads:
…as well as any other container/boxes that are collectively stored or found together with the aforementioned boxes and containers.
I read that as saying that everything in storage areas would be seized and looked at. The storage areas could be anywhere in Trump’s piece of Mar-a-Lago. No doubt teams of people are going through them page by page, since they found all sorts of papers in the previous boxes that weren’t part of this warrant.
However, that doesn’t seem to say that the FBI could look through every piece of paper that Trump possessed to see if by chance classified information was on them. A separate warrant would be necessary.
There’s also a discussion, now that the are released, that the warrant and the affidavit discuss the espionage act, which puts controls on defense secrets - and it is irrelevant whether the content is marked as such. if it’s detrimental to the defense of the USA to reveal the information, then certain careless behaviour with that information is criminal.
I saw a post of an image “The first page of the affidavit” and everything was blacked out except the word “ketchup”. 
A nice piece of satire.
Here’s the full affidavit for those who want to read it.
The affidavit only “discusses” the Espionage Act in the most technical way. A footnote on p. 22 clarifies some legal definitions with reference to the Act and many court decisions.