Fine, identify the leakers and prosecute them. At a minimum, pull their clearances, fire them, or ship them to Shimya or somewhere.
I would imagine these are mostly all GS-type employees (lower ranking), and you’d be stuck in a three-to-five year battle to yank clearances or dismiss them. You’d be better off to move them to a single-function job, with no access to the internet, and let them retire-out in ten to twenty years.
How about Incirlik? That place really sucks.