Is the President the Ultimate Arbiter of Classification in the United States Office?

There is this defence that has been made by some, i don't know if it's been formally made by the trump team. Some of trump friendly lawyers have made it that the president is the ultimate arbiter of classification in the united states office. What he declares to be classified is classified. And what he declares tobe not unclassified is presumably declassified. The law is not only terribly unclear on this, it's terribly wrong. He cannot de classify retroactively after he gets a sapina. So this will be largely an issue of fact. Is there a memorandum in the files? Are there witnesses? It's a defence. Is it a strong defence? It depends on the evidence