Moore is the co-founder of Intel who in 1965 came up with “Moore’s Law,” which predicted that computing power would double every year. The trend has kept up for two generations and counting, causing exponential growth in computers' ability to process information.
When Moore’s Law was conceived, and J. Edgar Hoover was at the height of his power running the FBI, a world in which the government could plausibly suck in all the data created by hundreds of millions of Americans or billions of earthlings was simply beyond imagining. (Well, not completely beyond imagining. George Orwell did a quite good job).
If you were a federal agent who wanted to intercept somebody’s mail, you had to go down to the post office to get it. If you wanted to wiretap a phone call, you needed to physically install a wiretap. Read, for example, John Judis’s account of being tailed by the FBI as a young radical in the 1960s and '70s, and think of the sheer manpower — and money —that was deployed to monitor every minor lefty activist of that era.
Of course, that variety of surveillance state was largely done away with in the post-Watergate reforms. Domestic spying was limited to investigations that obtained a warrant, which in turn required credible evidence of a crime before G-men could snoop. But the entire legal regime was still based on the premise that state monitoring of private communication was something that could only really be done by those traditional means of investigating a possible crime.
Fast-forward 30 years. Digital storage and computing speeds are such that it is within the technical capacity of the government to archive every telephone conversation on earth. I have at my fingertips, thanks to my Gmail account, every e-mail I have written since 2005, nearly 26,000 separate conversations -- and if Snowden’s accusations about the NSA’s Prism program are accurate, so does the National Security Agency (though there’s a lot we don’t know about what steps the government has to go through to exploit the technology). The Google servers alone contain vast quantities of information, instantly searchable, belonging to their many millions of customers, like me.
In proving Moore's Law, all the world's information can be stored, cataloged and accessed in ways that would make J. Edgar Hoover leap with delight.
Meanwhile, the old system of separating domestic and international spying is looking more and more antiquated. It’s fine to have a 1970s-era principle that the FBI can’t spy on radical citizen activists unless it has evidence that they are looking commit a crime, while the CIA can spy on the Soviets with few limits. But in a world where loose networks of terrorists incite our biggest fears and where information is pinged around the world with little respect for national boundaries, the old distinctions aren’t particularly useful.
What could or should the intelligence agencies have done with Tamerlan Tsarnaev, the deceased Boston Marathon bomber? He was a legal resident of the United States who was not known to have committed any crimes before the attack but may have had connections to Chechen radicals. These situations rapidly become a legal knot, and it's hard to know from constitutional principles exactly where the lines ought to be.
Couple that with the extreme secrecy around what exactly the U.S. government’s technical capacities are, and what legal authorities they are based upon, and you have a nasty combination. The people (up to and including the president) who know what Prism and similar programs are truly capable of argue that disclosing those details would make it too easy for bad guys to evade government monitoring. So we have to just trust that they aren’t overstepping any boundaries of legitimate civil liberties.
So, it's: Just trust us on this.
Put it all together, and we end up here: Technology has made possible the monitoring of private communications on a scale that was unthinkable a generation ago. The legal regime that governs use of that communications has evolved slowly to deal with that reality. And the people who actually know what the government is doing, and what it's capable of doing, say they can’t tell us those details. Is it any mystery why people are uncomfortable with what they've been learning in the last few days?