But in signing the bill into law last Friday, President Trump said he would not be bound by that restriction.

"Although I expect to be able to provide the advance notice contemplated by section 8009 in most situations as a matter of comity, situations may arise in which I must act promptly while protecting certain extraordinarily sensitive national security information. In these situations, I will treat these sections in a manner consistent with my constitutional authorities, including as Commander in Chief," he wrote in a May 5 signing statement.

More generally, Trump suggested that his power to classify national security information is altogether independent of Congress. "The President's authority to classify and control access to information bearing on the national security flows from the Constitution and does not depend upon a legislative grant of authority," he wrote.