Probably have to get it down to every mid-level functionary on up. Most of the secrets are generated by career bureaucrats. Sometimes politicians approve, but a lot of the government goes on with no input from anybody elected.
Hence the “think tank” misnomer. If the pols were on camera 24/7 that would include all documents and all people they were meeting with. I know that there would be work arounds, but how many people would go into public service if they knew that there was possibly no big payoff?