Without knowing more, I would think most counterintelligence work is still done by the FBI, CIA, NSA, and maybe DIA. But I was replying to the specific claim th

Without knowing more, I would think most counterintelligence work is still done by the FBI, CIA, NSA, and maybe DIA. But I was replying to the specific claim that there were no "designated ... agencies", where I interpreted designated to mean specialized. The FBI, CIA, and NSA are monolithic organizations.