BOB GARFIELD: From WNYC in New York, this is NPR's On the Media. I'm Bob Garfield.

BROOKE GLADSTONE: And I'm Brooke Gladstone. Last week, the New York Times reported that soon after September 11th, the National Security Agency began eavesdropping on American citizens. Under the Foreign Intelligence Surveillance Act, or FISA, the government can legally conduct such operations, as long as it obtains a warrant from a FISA court. But the NSA never sought those warrants, as the Times disclosed after holding its story for more than a year. We'll discuss why the Times took so long in a few moments but first, some background. The Foreign Intelligence Surveillance Act was enacted in 1978 to prevent the kinds of surveillance abuses common during the civil rights era and the Vietnam War. Since then, the FISA court has rarely denied a requested warrant. The big unanswered question, why the government didn't ask for any in this case. Here with some possible answers is William Arkin, author of the Washington Post blog Early Warning, which often addresses military and security issues. He says the administration had two reasons for sidestepping the FISA court.

WILLIAM ARKIN: The first is a justification on the part of the Administration that the timeframe for seeking a FISA warrant was too long, and thereby, they needed to move quickly. The second is that there are some technical changes which have occurred, realities associated with modern surveillance of potential terrorists, which necessitate the government not seek the permission of the court.

BROOKE GLADSTONE: Well, let's unpack those assertions. The first one about speed seems easily answered, since you could go ahead, surveil somebody, eavesdrop on someone, and under the FISA regulations you can actually acquire the warrant after the fact, right?

WILLIAM ARKIN: It has 15 days, and then 45 days as a threshold, under which you can still seek a warrant. So the argument, at least in itself that there was a need for quick movement on the part of the government, doesn't stand up to scrutiny, unless you combine it with the other argument that the government is making, which is that it is the nature of the information that they are collecting which necessitates them circumventing the FISA system.

BROOKE GLADSTONE: Explain that one to me.

WILLIAM ARKIN: Well, here's the rub. FISA is set up with the notion that what you are doing is you're seeking a warrant to surveil a person, Bill Arkin, so that you can conduct electronic surveillance or wiretapping or other types of surveillance of his e-mail, telephone calls, et cetera. But what if the government, in fact, is doing something very different after 9/11? They're not targeting a person per se. They are acquiring massive amounts of data - every telephone call between the United States and Pakistan or between the United States and Afghanistan, every e-mail message that transits a certain port in the United States. By the acquisition of that massive amount of data, what they are doing is they are inadvertently and promiscuously collecting information about and dealing with U.S. persons, but they're not targeting them until that information churns through various data mining and link analysis softwares, until they are then coming upon potential terrorists or potential Americans or U.S. persons who are linked to terrorism.

BROOKE GLADSTONE: The NSA does make a distinction, I guess, between what it calls "hunting" for information, as spying on you, Bill Arkin, might be, and "gathering," which is trolling the information networks for keywords and possible threats to the United States. So it would seem to me that this would call for a different legal response than that which is offered by FISA.

WILLIAM ARKIN: Well, I think that there's a valid case that the government is probably going to make in hearings before Congress in the coming days and weeks, that, in fact, the times they are a-changing, and that they require different mechanisms for conducting lawful surveillance.

BROOKE GLADSTONE: Well, if there was doubt about the legality of the program, why didn't the White House work with Congress to craft new legislation?

WILLIAM ARKIN: Perhaps it's the case that the notion that you're telling the American public that no e-mail, no phone call, no credit card receipt, no driver's license is safe any longer because with our new digital databases and capabilities we can suck all of that information together. I think the American public wouldn't have been very understanding, necessarily, of that new government capacity. Much of this information never even passes through human hands or is looked at by a set of human eyeballs. It is just churned through these layers upon layers of information extraction software tools. And I think for that reason, the 1978 law is no longer sufficient to protect American rights and civil liberties while the government is, in fact, protecting us.

BROOKE GLADSTONE: If all this information goes through, perhaps without human eyes ever seeing it, what's the harm?

WILLIAM ARKIN: Well, you know, I'll admit to you, Brooke, that when I first started thinking about this program after the New York Times stories, I thought to myself, "I'm not really worried about this because I know that the government is focusing its attention on a few elements of American society, mostly Muslims - let's be honest - who are connected to Pakistan, Afghanistan, the Middle East. Doesn't affect me." And I'll admit to you, that was my initial reaction. But it is the building of these tools and capacities to collect this enormous amount of information and then analyze it and aggregate it that opens the way for government abuses tomorrow. And so that's why we need to have laws which regulate what the government can collect and how it can collect it and how it can retain that information, not so that we can shield or protect those who may, in fact, be connected to transnational terrorist organizations but that we can protect American citizens in the future from any kind of government mischief should somebody want to undertake it.

BROOKE GLADSTONE: All right. Bill, thanks a lot.

WILLIAM ARKIN: Thank you.

BROOKE GLADSTONE: Bill Arkin is the author of "Early Warning," a Washington Post blog about national and homeland security.