article in the Atlantic.
https://www.theatlantic.com/ideas/archive/2022/08/trump-fbi-raid-classified-nuclear-documents/671119/
"While a president is president, Leonard told me, “the rules and procedures governing the classification and declassification of information apply to everyone else.” And that means Trump could have declassified whatever he wished (again, with specific limitations soon to be discussed) before carting it off to Mar-a-Lago. He would not have had to file paperwork—just “utter the magic words,” Leonard told me. He could have waved his hand over the U-Haul trailer as it headed out the White House driveway and down I-95 toward Florida, and there would have been no classified material in there to mishandle.
Leonard noted important caveats, however. First, Trump’s power to declassify ended with his presidency. Second, that U-Haul could be reclassified by someone else. (Depending on traffic and the sharpness of the Biden administration, I would imagine it could have been reclassified somewhere around Fredericksburg, Virginia.) And third, there are certain materials that presidents cannot classify and declassify at will. One such category of material is the identity of spies. Another is nuclear secrets."