You're not spelling out a scenario we can meaningfully dissect.

Probably you will agree, the leverage of a blackmail attack is not bottlenecked by the persuasiveness of the accompanying threat letter. It is bottlenecked by the existence of damning facts they would rather keep hidden, and the ability to discover those damning facts. I'll grant that automated discoverability of those damning facts is augmented by superintelligence; they can efficiently sweep the open internet in the blink of an eye, and sure, I'll concede, hack into most accounts at will. But that is still a small part of the process by which blackmail material is actually obtained in the real world.

> LLMs do not have to convince 1 specific person, 1 random person is sufficient

No, not one random person either, but many people in positions of great influence. There already exists blackmail and other corrupting influences on such persons in voluminous quantities. If the US targets the entire Russian admin, or vice versa, with AI-enabled blackmail discovery techniques, it will not be an augmentation of their preexisting operations to discover blackmail on each other in excess of the augmentation provided to software engineering generally by AI.