A "litmus test" issue might be whether you think the NSA's expressed surprise over Snowden's leaks was genuine. I tend to think it was, and that his documents are genuine. I see no reason for the NSA to be substantially more competent than, say, the OPM.
They're each large organizations with no bottom line that attract people of flexible moral character who are attracted to power and/or job security.
I don't think those traits tend to lead to effective organizations, as much as a number of Hollywood movies would like us to believe.