And for absolute certainty there is a standard process for declassifying documents.... They could do so for Hillary and Obama as well ...Trump should have seen this coming.
Hillary, while top dog (or would that be bitch?) at the State Department still did not have the power to unilaterally declassify anything, especially after she left office.
As for seeing it coming, President Trump was impeached the first time for what he allegedly said in a phone call as reported by an underling, and the second time for, what exactly? Not stopping people who were let into the Capitol by security holding the doors open for them? Trump was unprecedented since at least the time of Jackson, but Jackson made sure that everyone employed by him was loyal to him, “to the victor belongs the spoils”. The opposition to Trump from within his own government and party was unprecedented and is still going on as I type this.
I agree with almost everything you posted.
But I have a lot of personal experience with handling classified material. In simple terms the declassification starts with the President. So far so good. The request to document that decision is forwarded to the agency (CIA, FBI, NSA, DOD …) who issued the original classification. Typically the issuing agency replies with a list of recommended redactions. If the President approves of the redaction the declassification process is complete, all paper copies are stamped with an UNCLASSIFIED or a DECLASSIFIED stamp, classification markings are struck out and then signed by someone with the authority and dated.
If the President does not agree with the redactions he submits a redacted version that would be acceptable. So it is a negotiation. But, in the end, the President can dictate the final version - AS LONG AS HE IS STILL PRESIDENT.
Trump’s problems: He is no longer President and it is not clear as to whether there is any actual proof that this process was initiated in all cases. We do have proof, I believe, that it was initiated in at least some cases.
And the overriding question that the lawyers should be able to answer: At what point in this cycle is the document actually declassified, at the wave of the hand stage (we hope) or at the completion of the process.