The first caveat: While Trump has the power to declassify information, he doesn't appear to have done that in this case, at least at the time the story broke.
"There's no question that the president has broad authority to declassify almost anything at any time without any process, but that's not what happened here," said Stephen I. Vladeck, professor at the University of Texas School of Law. "He did not, in fact, declassify the information he shared with the Russians, which is why the Washington Post did not publish that information."
Instead, Vladeck said, Trump "took it upon himself to authorize officials from a foreign government to receive classified national security information that was itself derived from a different foreign government's intelligence gathering. That's just not the same thing as what Sen. Risch described, and the law on this topic is far murkier."
OOps