Now think about what that means.

If NBC's reporting is accurate, Alexander's assurance that "we can audit the actions of our people 100 percent, and we do that," is a lie. To be more precise: We've long known that the NSA doesn't audit all its employees 100 percent, since what Edward Snowden took is still unknown. NBC suggests that the NSA isn't even capable of fully auditing systems administrators.

NBC also gives us even more reasons than before to dismiss the talking points of NSA defenders like Rep. Peter King, who claims that the NSA has a 99 percent compliance rate. He has no clue what those 1,000 systems administrators are doing with the system. Already, one has taken extremely sensitive information, fled to Russia, and gotten temporary asylum. Yet the NSA expects us to trust the other 999 systems administrators it has vetted and whatever oversight is in place to monitor them. They've already proved themselves undeserving.

Of course, systems administrators acting out on their own aren't the only potential problem.

Imagine that President Obama, or President Hillary Clinton, or President Marco Rubio, or the person any of them chooses as director of national intelligence or director of the NSA, wants to abuse surveillance data. The vaunted audits and oversight of NSA analysts would be totally irrelevant. It wouldn't matter if analysts were achieving 100 percent compliance. If the NBC story is correct, spying on political enemies would still be as easy as having one cooperative systems administrator. Unless I've missed it, the federal employees who keep assuring us that serious abuses would be very difficult to pull off haven't addressed the systems administrator loophole.

There's good reason to worry that getting around the safeguards we keep hearing about is as easy as placing one person in the right job. How hard would it be for Obama or Director of National Intelligence James Clapper or Alexander or hypothetical Presidents Clinton or Rubio to have a friendly NSA systems admin to pass them information? How tempting would it be? (It tempted presidents before.) How would the Senate or House intelligence committees know of abuses perpetrated by a systems administrator like that? If you assume that the NSA has obviously anticipated this problem, note that they didn't anticipate Snowden -- or if they did, they weren't able to stop him. Was anyone fired for that?

It all comes back to what I wrote in early June. We've provided the NSA with all the infrastructure a tyrant -- or a Richard Nixon -- would need. "More and more, we're counting on having angels in office and making ourselves vulnerable to devils," I wrote. Devils with system admin privileges. If Alexander succeeds in culling their ranks, there will still be 100 from which to chose, plus however many a future NSA head decides to add -- in secret if that's what he or she wants. And we've already seen how much unanticipated havoc just one systems admin can cause.