Everybody who has access to secrets is a target of opportunity. Leaders should expect their phone to tapped and their messages read. A smart leader could take advantage of that. Nothing holds more weight than a secret that the enemy teased out and is certain they got on their own.
Of course. Disinformation is a primary tool of clandestine services. They've even admitted it years ago. It's all a game of chess. The sad thing is our elected politicians use disinformation to influence the populace.