Well, they took Trump’s EO eliminating Obama’s EO creating DACA to Court and got a friendly judge to suspend Trump’s EO..Trump’s EO on the travel ban was taken to court and held up there for a very long time.
I see no reason why they wouldn’t fight a Declassification EO the same way...using some California or Hawaii or D.C. judge to hold it up for awhile on any kind of National Security grounds they can cook up. They can say Trump plays fast and loose with national security...he posed for pics with a dictator and called off Korean military maneuvers and invited Kim to America...he even said nice things about him! That’s enough for a leftist judge to stop the EO right there. They are playing for keeps. They won’t blanche at an EO.
“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.”
Even politifact had so admit it was possible...