Or what if a higher-up at the NSA didn't panic, but exploited the panic of everyone else?

Unless the NSA is reined in, it is all but certain that future abuses will occur. The question its defenders ought to be asked is, "Would you support these programs even if you knew future abuses were inevitable?" True, every law-enforcement tool is abused at one time or another. But the consequences of NSA abuses are catastrophic in a way without precedent in American history because their law enforcement tool contains private information about almost every citizen.

How many government officials could be blackmailed with already collected material that no one has looked at ... yet?

The NSA is nevertheless out with another defense of its program. The statement, posted online Wednesday, is worth a close look. "The implication that NSA's collection is arbitrary and unconstrained is false," it begins. Recall that this is an agency that collects metadata on all phone calls. In other words, its approach to data collection isn't "arbitrary," it's virtually comprehensive. "NSA's activities are focused and specifically deployed against -- and only against -- legitimate foreign intelligence targets in response to requirements that our leaders need for information necessary to protect our nation and its interest," the NSA's statement continues.

Let's read carefully.

The NSA's activities may be "focused and specifically deployed against -- and only against" foreign targets. But the fact that it isn't "focused" on American citizens doesn't mean their phone data, Internet behavior, and other information isn't being collected in vast, searchable databases. If and when access to that information is abused, the focus of the program that first collected it won't matter.

The NSA says:

XKEYSCORE is used as part of NSA's lawful foreign signals intelligence collection system. By the nature of NSA's mission, which is the collection of foreign intelligence, all of our analytic tools are aimed at information we collect pursuant to lawful authority to respond to foreign intelligence requirements - nothing more.

The analytic tools may be "aimed at" information relevant to foreign intelligence. That doesn't mean that those same tools aren't hoovering up lots of domestic information with no relevance to foreign intelligence, or that an abuse-minded NSA employee couldn't aim the tools elsewhere.

NSA:

Allegations of widespread, unchecked analyst access to NSA collection data are simply not true. Access to XKEYSCORE, as well as all of NSA's analytic tools, is limited to only those personnel who require access for their assigned tasks. Those personnel must complete appropriate training prior to being granted such access - training which must be repeated on a regular basis. This training not only covers the mechanics of the tool but also each analyst's ethical and legal obligations. In addition, there are multiple technical, manual and supervisory checks and balances within the system to prevent deliberate misuse from occurring.

In other words, analyst access to the data isn't "widespread and unchecked," it is widespread and checked. Given the secrecy surrounding the agency, it is actually impossible to verify the system of checks. But even presuming that there is excellent ethical training, as well as "multiple technical, manual and supervisory checks and balances within the system to prevent deliberate misuse," the same can be said of the U.S. military, the IRS, the NYPD, the prison at Gitmo -- serious abuses happen all the time in government agencies despite government training and checks and balances. Operating as if they won't ever happen is ahistorical and reckless.