"Fareed Zakaria GPS," Sundays at 10 a.m. and 1 p.m. ET on CNN

Fareed speaks with Michael Hayden, former director of the CIA and National Security Agency, about tackling terrorism in the wake of the Boston attack.

So is there some system for stopping this in the future?

If you look at any attack, particularly looking into the rearview mirror as opposed to looking through the wind screen, you can judge that it could have been prevented. This was preventable if…let me also offer you the view that attacks of this nature are inevitable. This is like penalty kicks in soccer. No matter how good the goalie is, sooner or later, this ball is going into the back of the net. And I don't mean to be so dark for your viewers, but they have to understand that we’re working in a part of the spectrum now that is well below what we experienced more than a decade ago.

I mean, what happened in Boston was a tragedy, truly a tragedy. But it wasn’t a catastrophe. And if we force our enemies to work in that band where, from the outside looking in, if it's hard to tell whether this was a high end crime or a low end terrorist event, that's a measure of our success, preventing our enemies from doing that which they want to do – a mass casualty attack against the iconic target.

But suppose you have a few of these people and they get radicalized on the Internet and they learn how to make this stuff, through Inspire magazine or other...

Right.

There's lots of information on the Internet outside of al Qaeda sites.

Yes.

Is there something you could do? You ran the National Security Agency.

Yes.

You can eavesdrop on conversations.

Yes.

What could you do?

Look, there are probably things you could do on the margin that reduce the odds of this a bit, but I've taken to describing our efforts out here like this. And they're good enough now that those things that used to really frighten us – 9/11, World Trade Center I, airliners over the Atlantic – very, very unlikely.

More from CNN: Missed signals

Now what have you got? You've got Boston. You've got Little Rock. You've got Najibullah Zazi trying to come here to New York. And now the question I ask the American public as an intelligence officer is, so what do you want me to do with my arm? I mean I can push it down a bit. I can buy you marginally more safety, but at what cost? At what cost in your privacy? At what cost in your comfort, what cost in your convenience, at what cost in your commerce? I mean these are all very serious questions and the folks inside the American intelligence community will respond to the public. They'll do what you tell them to do. But as a citizen, my judgment is that's about where we want it to be. If you push this down much further, we do what I've said we haven't done to date, which is we begin to change our DNA as a free people.

Now, Fareed, the dark side of that is, as I said before, this is penalty kicks. This is going to happen. It's a level of risk that, I'm very disappointed to say, we're probably going to have to live with.

When you look at the situation of the older brother going to Chechnya or Dagestan, the Russian intelligence tipping us off, was there anything there that should have been done differently?

You know, you look back and even those of us who are sympathetic to how hard a problem this is will say, boy, I wonder if and could we have done that? But let me give you a couple of factors. How many tips do you get in a week? And the answer is, you get an awful lot. And now this one came, apparently, from the FSB, from the Russian service. Now, Fareed, as you well know, the Russians are mad at a bunch of Chechens. Not all of them are terrorists and not many of them are dangerous to the United States. So you've got that factor. And then the travel to Dagestan probably wasn't the alerting thing to us that it would have been had he gone to Waziristan...

Right.

…where threats to the United States have been generated. So, we'll probably change our checklist. We'll probably add a few questions to those FBI interviews. Look, we'll let the facts take us where they will. But I'm a little reluctant to just facilely criticize the Bureau or anyone else on this yet.