The basic government defense of the NSA's bulk-collection programs—whether it be the list of all the telephone calls you made, your email address book and IM buddy list, or the messages you send your friends—is that what the agency is doing is perfectly legal, and doesn’t really count as surveillance, until a human being looks at the data.
It's what Director of National Intelligence James R. Clapper meant when he lied to Congress. When asked, "Does the NSA collect any type of data at all on millions or hundreds of millions of Americans?" he replied, "No sir, not wittingly." To him, the definition of "collect" requires that a human look at it. So when the NSA collects—using the dictionary definition of the word—data on hundreds of millions of Americans, it’s not really collecting it, because only computers process it.
The NSA maintains that we shouldn't worry about human processing, either, because it has rules about accessing all that data. General Keith Alexander, director of the NSA, said that in a recent New York Times interview: "The agency is under rules preventing it from investigating that so-called haystack of data unless it has a 'reasonable, articulable' justification, involving communications with terrorists abroad, he added."
There are lots of things wrong with this defense.
Second, it's unconstitutional. The Fourth Amendment prohibits general warrants: warrants that don’t describe "the place to be searched, and the persons or things to be seized." The sort of indiscriminate search and seizure the NSA is conducting is exactly the sort of general warrant that the Constitution forbids, in addition to it being a search by any reasonable definition of the term. The NSA has tried to secretly redefine the word "search," but it’s forgotten about the seizure part. When it collects data on all of us, it’s seizing it.
Third, this assertion leads to absurd conclusions. Mandatory cameras in bedrooms could become okay, as long as there were rules governing when the government could look at the recordings. Being required to wear a police-issued listening device 24/7 could become okay, as long as those same rules were in place. If you're uncomfortable with these notions, it's because you realize that data collection matters, regardless of whether someone looks at it.
Fourth, creating such an attractive target is reckless. The NSA claims to be one of the biggest victims of foreign hacking attempts, and it’s holding all of this information on us? Yes, the NSA is good at security, but it’s ridiculous to assume it can survive all attacks by foreign governments, criminals, and hackers—especially when a single insider was able to walk out of the door with pretty much all their secrets.
Finally, and most importantly: Even if you are not bothered by the speciousness of the legal justifications, or you are already desensitized to government invasion of your privacy, there is a danger grounded in everything we have learned about how humans respond when put in positions of unchecked power. Assuming the NSA follows its own rules—which even it admits it doesn’t always—rules can change quickly. The NSA says it only looks at such data when investigating terrorism, but the definition of that term has broadened considerably. The NSA is constantly pushing the law to allow more and more surveillance. Even Representative Jim Sensenbrenner, the author of the Patriot Act, says that it doesn’t allow what the NSA claims it allows.
A massive trove of surveillance data on everyone is incredibly tempting for all parts of government to use. Once we have everyone’s data, it’ll be hard to prevent it from being used to solve conventional crimes and for all sorts of things. It’s a totalitarian government's wet dream.