The Democrats and the left are not talking about Trump because they can't let him go- it's because he won't SHUT UP! and his supporters continue to undermine out democratic institutions.
And NO - a president cannot declassify documents merely by "thinking" about it..Jeesh get a grip
And it is NOT only about classified documents- NONE of the documents Trump too belonged to him- presidential documents belong to the government and Trump STOLE them
And the 1987 SCOTUS decision you refer to does NOT say what you are asserting!