This would seem to be a no-brainer: the CIA is actively trying to overthrow the democratically elected leader of THIS country, which makes them his enemy, which makes anything that weakens them good. It is hard to see how anything vindicating the CIA would be contained in those files.
Alternatively, depending on how desperately they want those files suppressed, he could use this as a weapon to force them into a MAJOR house-cleaning, one which would happen long before the October deadline. We need an agency that works FOR America, and it seems to me a lot of heads need to roll to make that happen–and in the process they need to just be retired, not allowed to hire on immediately with a private corporation that seeks the same ends, but funded by foreign governments and who knows who.
It is interesting that Obama had the opportunity to allow–apparently it happens unless stopped, which means he stopped it–the release of the files on the Bay of Pigs invasion. All accounts point to a feckless and cowardly JFK abandoning his soldiers on the beaches of Cuba at the first sign of resistance. The historians I read argue that the Russians saw this and concluded he was a pussy, and this is what created the Cuban Missile Crisis, which far from being a sign of his genius and leadership, was the outcome of more or less secret failures he had been able to suppress.
By law the cycle is 25 years. However, it does seem to me that the President ought properly to be able to order the declassification of anything he chooses, at any time he chooses. He runs the intelligence agencies. The law simply states that there will be an automatic declassification.
If I am right, this might be an interesting project for Trump: combing through secret files and determining what will most embarrass the people trying to embarrass him right now, and releasing that data, or holding it, subject to them acting like fucking patriotic Americans.
What he could do IMMEDIATELY is put somebody intelligent that he trusts on the project of reading through these files, which could contain very, very explosive information, and figuring out some combination of what is right and what is practical. Those decisions would depend on the details.
And what if the CIA WAS in some way behind the assassinations? That would mean they have been involved in internal regime change since at least the early 1960’s. Surely that is something Trump would want the American people to know, especially since that same CIA was capable of hiring, in 1977 or so, a John Brennan who voted for the Communist in 1976.