"Legal effect"; I think that is a good term to use here.
What are the limits to the authority of Congress to dictate how a President handles national secrets? Could Congress demand that the President inform Congress each and every time a document is classified or declassified? Could Congress legislate that classification lapses automatically after 30 days? Could Congress dictate that the President's State of the Union address is classified and that the President does not have the authority to declassify it.
Help me understand the limits of Congressional action and then I can better explain my position. I maintain that the President is simply not bound by the classification system. It's a tool that he can use to do his job. He is the master not the servant of that tool.
This isn't about Congress at all, or about any procedures it might have established regarding the President and classified information.
The question is, how does anyone know whether or not Trump actually declassified documents while President. What is the evidence that he did that, by any method at all?