re: Can someone tell me why Donald Trump is a threat....

HVAU. You do know that by DJT taking the documents from the white House BEFORE he left which was a couple of days before JB was sworn in that that act alone makes them declassified? There is no special procedure that he would have to go through to declass them. The constitution gives the president the sole ability to do that in anyway he/she chooses. So they were declassified as soon as they left the White House.