You mean like the background checks and audit trails that prevented Snowden from absconding with all those documents?
Background checks don't stop people who think they are righteous and audit trails are only as good as (a) the audit policies and (b) the auditors. Snowden was pretty explicit with his claims that putting down any half-assed justification was enough to satisfy the auditors.
This is a baffling comment. Are you aware of the background checks that NSA do on staff? And the audit-trails on access to various bits of data?