I wrote this in 2015 concerning HC's e-mails but it still applies. Restating the case, the classification system in the US exists solely by Executive Order. It does not exist by law. All classifications of information are derivative from the sitting president's Executive Orders on the subject. These are generally re-issued by each new president. Classification is administrative in nature and not based in law although disclosures that are not authorized ultimately by POTUS' authority ARE subject to criminal penalties. No cabinet secretary, Congressional body or other official has any legal authority to block a declassification order from the president.
" To be properly classified, a classification authority (an individual charged by the U.S. government with the right and responsibility to properly determine the level of classification and the reason for classification) must determine the appropriate classification level, as well as the reason information is to be classified. A determination must be made as to how and when the document will be declassified, and the document marked accordingly. Executive Order 13526 describes the reasons and requirements for information to be classified and declassified (Part 1). Individual agencies within the government develop guidelines for what information is classified and at what level" Wiki on classification in the US.
God himself does not personally "classify" information, not even in the US Government. He leaves that task to mere mortals. People who have security clearances and who are given access to documents marked with some jumble of letters indicating a degree of secrecy usually assume that there is something inherent in the information or the document that made it "classified." That is not the case. Information does not become "classified" until a "classification authority" says it is classified. In each department of the Executive Branch of the federal government the ultimate "classification authority" is the cabinet officer who heads that department, i.e., the Secretary of ——–.
In the case of the State Department, that "classification authority" was Hillary Clinton whilst (I been watchin;' Brit TV again) she was Secretary of State, Sooo, unless she ruled that something circulating within State was "classified," it was not.
In the case of something from another department that came to her already "classified" that would be a more complex "call," but not a simple "call." Normally, information coming to a departmental secretary has more than one source. Who can say what information came from where? Sooo, let up, people. pl