Did NSA underestimate the insider threat?

In this edition of the Irari Report, Ira Winkler and Araceli Treu Gomes continue their interview of Chris Inglis, former Deputy Director of NSA. In this segment, they focus on how an organization that is so aware of the insider threat can be compromised by a person like Edward Snowden.
Inglis highlights how trust is critical to function, but verification must be implemented. This relies upon a stringent screening process, as you have to extend to trust to the people you hire. While Snowden was