People are saying he released "classified: information, the thing is though he has the power to do that at will.
Experts agreed that the president, as commander-in-chief, is ultimately responsible for classification and declassification. When someone lower in the chain of command handles classification and declassification duties -- which is usually how it’s done -- it’s because they have been delegated to do so by the president directly, or by an appointee chosen by the president.
The majority ruling in the 1988 Supreme Court case Department of Navy vs. Egan -- which addressed the legal recourse of a Navy employee who had been denied a security clearance -- addresses this line of authority.
"The President, after all, is the ‘Commander in Chief of the Army and Navy of the United States’" according to Article II of the Constitution, the court’s majority wrote. "His authority to classify and control access to information bearing on national security ... flows primarily from this constitutional investment of power in the President, and exists quite apart from any explicit congressional grant."
Steven Aftergood, director of the Federation of American Scientists Project on Government Secrecy, said that such authority gives the president the authority to "classify and declassify at will."
In fact, Robert F. Turner, associate director of the University of Virginia's Center for National Security Law, said that "if Congress were to enact a statute seeking to limit the president’s authority to classify or declassify national security information, or to prohibit him from sharing certain kinds of information with Russia, it would raise serious separation of powers constitutional issues."