FOUR THOUSAND???

This is no way to run a hush-hush intelligence program!  From the WaPo's article on the "black budget" -

Long before Snowden’s leaks, the U.S. intelligence community worried about “anomalous behavior” by employees and contractors with access to classified material. The NSA planned to ward off a “potential insider compromise of sensitive information” by re-investigating at least 4,000 people this year who hold high-level security clearances.