You have to root them out and catch them in something like this, one person at a time.
This is a real problem in ALL the departments. It is the source of the leaks and rumors at the Pentagon and at State. Ashcroft did some fancy re-assigning in 2002 and has these folks fairly isolated. However, CIA obviously still has Clinton people there (like the odious Valeria Plame) and I am sure there are many more.
I am also sure they are being investigated quietly and watched so that anything at all untoward will give an excuse to get rid of them, like this person.
I certainly hope so!