The U.S. Has An 'Active Cyber War Underway' To Thwart The North Korean Nuclear Threat

New York Times reporter David Sanger talks about North Korea's nuclear program and warns that the regime, which has been "fodder for late night comedians for many many years," is no joke.

TERRY GROSS, HOST:

This is FRESH AIR. I'm Terry Gross. When President Trump came into office, President Obama warned him that the growing threat from North Korea's nuclear weapons and missile programs were likely to be the most urgent problem he would confront. That's according to our guest, New York Times national security correspondent David Sanger, who's been reporting on the North Korean nuclear threat.

Sanger says the regime is getting closer to being able to launch a nuclear weapon that could reach American shores. And now the U.S. is resorting to cyberattacks to try and undermine the North Korean missile program. Sanger also reported on the U.S. cyberattack on Iran's nuclear program with the computer worm known as Stuxnet. That's described in his book "Confront And Conceal: Obama's Secret Wars And Surprising Use Of American Power."

David Sanger has written for The New York Times for 30 years and has worked on two teams that won Pulitzer Prizes. He spoke with FRESH AIR's Dave Davies.

DAVE DAVIES, BYLINE: David Sanger, welcome back to FRESH AIR. North Korea's nuclear program has been a serious security concern for a long time for the United States. You write that three years ago, the Obama administration ordered the Pentagon to step up cyber and electronic strikes against North Korea's missile program. What are we talking about?

DAVID SANGER: Well, Dave, thanks for having me back on. And what we're talking about here is a new way to think about defeating or delaying the possibility of an attack by a rogue state like North Korea. A new way because if you think about our traditional missile defenses, it has been since the Eisenhower era an effort to go build what people call a system in which a bullet can hit a bullet. Somebody shoots a missile, we shoot something up in the air, try to intercept it. In its most glorious version, this was the Star Wars plans of Ronald Reagan. In their more day-to-day plebeian uses, this is what the Israelis do with Iron Dome which intercepts short-range missiles and what the United States has attempted over the years.

The U.S. since Eisenhower has spent $300 billion trying to develop these kinds of systems. And the early tests on this have not been reassuring. Under perfect conditions, where the Pentagon knows that a missile's about to be launched and roughly where it's going to appear, we have a failure rate of about 56 percent. And that's intercepting long-range missiles. A higher success rate against short-range missiles.

And so the question that President Obama faced was if you've got a rogue state like North Korea coming along developing an ICBM, can you rely on this system to defend the United States? And I think it seemed pretty obvious to him that the answer to that was no and he needed another layer, another approach. And left-of-launch, defeating these missiles before they're launched, was that approach.

DAVIES: What's striking to me about this, and when I read this in your piece, I think a lot of us thought, you know, a North Korea with nuclear weapons is a scary thing for a lot of people. But surely if they tried to attack the United States, a missile would have to cross the Pacific Ocean. We'd see it coming. There would be plenty of time to react. In fact, it's a very real threat, isn't it?

SANGER: It is a real threat. Now, so far, the good news is the North Koreans have not developed a missile that can make it across the Pacific. Or at least they haven't tested a missile that can make it across the Pacific. And, you know, developing an intercontinental ballistic missile is no easy task. It took us years in the '50s and took the Soviets years in the '50s to do it because the missile goes out of the atmosphere and then has to re-enter. And there are huge stresses on it. And there are huge problems in developing accuracy.

But most of the best estimates are the North Koreans will be there in the next couple of years - three, four, five years. Now people said that five years ago as well. But they have so stepped up their testing capability that there's good reason to think they will reach that milestone. And then the question is, do we have an effective means beyond the traditional missile defense to go stymie that? And that's the problem that President Obama was dealing with in secret in early 2014.

DAVIES: OK. And so apart from the anti-ballistic missile system trying to knock it out of the sky, they developed these cyber and electronic means. How does this work?

SANGER: Well, the way this works is that you try to defeat the missile before it launches or in its early moments of launch. And so this is part of a program the Pentagon has been pushing somewhat in the open. A lot of the documents for this we found in the open describing the technology, even though it didn't refer except in a few specific cases to North Korea. But a lot of these methods they've been trying under the rubric of left-of-launch. If you think of left-of-boom, the phrase you heard so often in Afghanistan and Iraq, which was how do you defeat a - an IED before it explodes? Find it and disable it.

Left-of-launch is the same concept. How do you defeat a missile before or right during the launch? And the idea is to get in using a cyber weapon to get into the missile systems, whether it's a guidance system, a computer system, a system that communicates the sort of headquarters to the missiles, so that you can interfere with that and keep them from ever launching it. Or if it does launch, send it off into the water in its opening moments.

DAVIES: Is there evidence that it's been effective?

SANGER: Well, there is certainly circumstantial evidence that it has been effective. The program that President Obama approved in early 2014, which I think you could say and we can come back to this later on is sort of a follow-on to a different kind of cyber program he approved in the early days of his presidency to use against Iran's nuclear program. But this program was really aimed at the intermediate-range missile - something called the Musudan missile - that the North Koreans were testing on their way to making an ICBM.

And the origin of this story, Dave - in many ways, the origin of our writing about it - was that my colleague Bill Broad, with whom I've worked since the space shuttle Challenger investigations back in 1986, he and I were sitting discussing the North Korean launches one day. And we were looking at the string of failures. Remember all the times you'd pick up the paper and you'd read, you know, North Korea tries to launch a missile and it fails?

DAVIES: Right.

SANGER: And we looked at the numbers. And we realized that the failure rate on the Musudan was 88 percent. Now, this for a country that hired a lot of former Soviet scientists after the Berlin Wall fell and after the Soviet Union dissolved, brought them to Pyongyang, bought a lot of their technology and in their early days had a very high success rates with the North Korean missile program because they were basing it on experiences that the Soviets and later Russia had had. And suddenly, their failure rate soared.

Now, the problem we ran into, Dave, in the course of the interviewing for this and of course of our other research, is that for any given launch it's very hard to say what went wrong. Could have been electronic interference, cyber interference by the United States. But it could have been bad welds, bad parts, bad luck. And the North Koreans have had a mix of all of those. And it's easy to forget that if you go on YouTube and you look up early U.S. missile launches...

DAVIES: Right.

SANGER: ....We dropped a lot of missiles into the drink as well.

DAVIES: Right. Is this kind of cyber effort - how is it alike or unlike the Stuxnet worm that was used to disrupt the Iranian nuclear program?

SANGER: Well, it's a good question. And the commonality here, Dave, is that you're using cyber means or electronic means - and sometimes there's a distinction between those two - to accomplish a result in the real world. So in the early days of cyber, we thought it was just sort of computer-on-computer battles. You know, I go after your computer system, you go after mine. Maybe I go after your bank account that's linked to a computer system.

But in the Iran case, we had the first case in which the United States - in a secret program code named Olympic Games - went after a physical system. In that case, an enrichment plant underground at Natanz in Iran. And the purpose of the cyberattack was to sabotage the plant in a way that previously you could only do by bombing it from the air or maybe sending in saboteurs on the ground. In this case, what they did in the Iran case was that they got into the computer systems and forced the centrifuges, which are these giant machines that spin at supersonic speeds to enrich uranium, forced them to speed up or slow down until they exploded. And that worked for about a year or a year and a half.

Eventually, the code leaked out - nobody's fault but it got out. And the Iranians got a copy of it, and they figured out how to go defeat it. And I worked between 2010 and 2012 on a book called "Confront And Conceal" that included and opened, actually, with the scene of President Obama discovering that this code had gotten out and that this program on which they had spent millions if not hundreds of millions of dollars had become known to the Iranians, the Chinese, the Russians and others.

And they had to decide whether to suspend it. The North Korea program is, in many ways, more difficult because in the Iran case, you were going after a fixed plant underground. If it didn't work today, you could work on the code and come back next week. In the North Korea case, you have to go after missiles and you have just seconds to be successful at that moment of launch.

DAVIES: So you're sending - you're somehow acquiring discerning software codes that would affect the missile and then sending a signal - what? - from a satellite that disrupts it?

SANGER: There are all kinds of ways that you can send it. And I'm not being coy with you. As we worked on this story, we understood its sensitivity and deep classification. And in the course of conversations we had at very senior levels of the U.S. government - people were obviously concerned with it - we agreed to keep out of the story the how that they are going about this in an effort not to help the North Koreans figure out how to defeat it. On the other hand, we thought it was very important to describe, as we did in the Iran case, the what the U.S. is doing because there's a huge important roiling debate that the government has kept pretty well suppressed about how we use these cyber weapons because we are, of course, the most vulnerable country on earth to cyberattack ourselves.

And so one of the big decisions the United States needs to make, just as we made these decisions with nuclear weapons, chemical, biological weapons and ultimately with drones, is do we want this to be an everyday weapon in our arsenal if it can be used against us in such a devastating way as well?

DAVIES: Right, you know, I remember the debates about the anti-ballistic missile systems decades ago. And people talked about how even though they were defensive weapons, they were scary and destabilizing because it meant if we can knock out our ability to retaliate, it increases the advantage of a first strike. Is something like that at work here?

SANGER: The exact same debate is at work here. So the North Koreans have certain cyber skills obviously against the United States. They did a very successful attack against Sony Corporation. We ran a story the other day about how they managed to steal money from the Bangladeshi central bank using some very innovative cyber means. We don't think they've got the skills to get into the American nuclear arsenal. But let's say for a moment that you took what we're doing with North Korea and you expanded it to go use it against the Russians or the Chinese.

And the Russians and the Chinese, of course, see what we're doing with North Korea, and they say, well, of course they'll try to use that against us. They would then be tempted to do the same thing against our own nuclear forces. And that does raise a destabilizing scenario. And the scenario's like this that right now we've got a balance of power that comes out of mutually assured destruction. No one's going to launch against us because they know we could launch against them.

But supposing the opposition group, whether it's Russian or Chinese or someone else, thought, you know, we secretly have gotten inside the American nuclear arsenal and we could launch against them. And when they go to press a button, nothing will happen or it won't happen the way they think it will. Then you're increasing the temptation of an adversary to go attempt a first strike. So it's very similar to the debate about the anti-missile systems.

DAVIES: We're speaking with David Sanger. He is a national security correspondent for The New York Times. We'll continue our conversation in just a moment. This is FRESH AIR.

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DAVIES: This is FRESH AIR, and we're speaking with New York Times national security correspondent David Sanger. Lately, he's been writing about the North Korean nuclear threat. So a few years ago, the Obama administration undertakes this effort to use cyber and electronic means to disrupt Korean - North Korean missiles. Seems to work, although it's not clear how often there might have been other causes. Where does it stand today? Have the North Koreans had more success in developing their missile program?

SANGER: Well, it's a little bit unclear to us where it stands today. As of last fall, the North Koreans seemed to detect or suspect what was going on. And they suspended the flights of these Musudan missiles. North Korean defectors, who are not always the most reliable source but frequently have some good information, have said publicly in press conferences in Seoul that the North Koreans are in a witch hunt right now to go find what's gone wrong here, figure out whether there's an insider threat, figure out whether they have spies within the system.

In many ways, the United States is perfectly happy to have them on that search because I think they believe that it results in purges and disruptions and makes it very difficult for the North Koreans to proceed on schedule, so there hasn't been a Musudan launch since the fall. But they have launched some other intermediate-range missiles that are based on a different solid-fuel technology instead of the liquid fuel in the Musudan. And those have been more successful, including the one that got launched the night that President Trump was having dinner with Prime Minister Abe of Japan in the Mar-a-Lago dining room. And you remember those photographs that showed them all with their iPhones looking at reports about the North Korean success - obviously, an issue of great concern to Japan because these solid-fuel rockets, like the Musudan, can reach just about any place in Japan and many parts of Japan and South Korea where there are American military bases.

So both the U.S., Japan and of course South Korea as well have deep concerns about these. It's an interesting question, why the program appears to have been less successful against this new generation of rockets and whether or not that's just a temporary phenomena. Remember, there is nothing permanent when you're doing a cyberattack. It's always changing because the system that you're attacking is always changing.

DAVIES: Let's look at a little bit of history here. You know, there are a number of Communist regimes in the 20th century we could think of, like Cuba and North Vietnam, that didn't work on developing their own nuclear programs. I mean, it's a lot of effort to do this. Why, for decades, has North Korea been so focused on this goal?

SANGER: You know, it's a fascinating question, David. In the late 1980s, I was fortunate enough that the Times assigned me, at age 28, to go over and be a correspondent in Japan in our Tokyo bureau, which covers the Korean Peninsula as well. And so starting in the late '80s, I started digging into this and wrote some of the first big stories that were in popular media about a secret North Korean site called Yongbyon, which is their major nuclear development site. Then it was before the North Koreans had successfully tested their first nuclear weapon - years - decades actually before they did that. They did that in 2006.

And if you look at this from the North Korean perspective, it makes enormous sense to have your own nuclear weapon. First of all, the founder of the country, Kim Il Sung, remembers that General MacArthur, during the Korean War, wanted to use nuclear weapons against North Korea and China. He was stopped from doing this. But it made a very big impression on Mr. Kim, and he knew that North Korea, to survive and deter attack, needed to have this capability itself. And he's the one, the grandfather of the current North Korean leader, who started down this path.

Then, later events confirmed in the North Korean mind that they really did need this. Give you an example - think about what happened in Libya. Now, you may remember that the Libyans were thinking about building their own nuclear weapons. And they purchased a huge amount of the technology from A. Q. Khan, who was one of the founders of the Pakistani nuclear program. And they brought a lot of the material over, including the centrifuges needed to produce uranium - or enrich it and begin to make the fuel for a nuclear weapon. They brought it over to Libya.

And then after the Iraq War began in 2003, they got caught at this, and they decided to give it up. And they did give it up. All that equipment was shipped back to the United States. It's now sitting in Tennessee. And the Libyans decided to go integrate with the West. And there were early efforts to go do that throughout the Bush administration. But you know this story. The Arab Spring came along. The Libyan people had an uprising against Moammar Gadhafi. And ultimately, Gadhafi was put on the run, chased across the country, found in a ditch and executed.

So if you're the North Koreans and you look at the Gadhafi example, what do you say? You say - you know, if they had gotten anywhere with their nuclear weapons program - if they hadn't given it up, maybe the West wouldn't have been so eager to go contribute to bombing them and running Gadhafi out of town. So everything that we did in Libya and some other places around the world has sort of confirmed the North Korean worldview that these weapons offer you a form of security you're not going to get any other way.

GROSS: We're listening to the interview FRESH AIR's Dave Davies recorded with David Sanger, a New York Times national security correspondent. After a break, they'll talk more about why there's no good option for dealing with North Korea's nuclear threat. And Maureen Corrigan will review a new novel about a father's corrosive relationship with his two sons. I'm Terry Gross, and this is FRESH AIR.

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GROSS: This is FRESH AIR. I'm Terry Gross. Let's get back to the interview FRESH AIR's Dave Davies recorded with David Sanger, a national security correspondent for The New York Times who has been covering North Korea's nuclear and missile programs. The regime is getting closer to being able to launch a nuclear weapon that could reach the U.S., and the U.S. is waging cyberwar against North Korea to try to undermine its missile program.

DAVIES: You know, it might be a good point to discuss your view of the North Korean regime. You know, I think to a lot of people, they seem, you know, erratic, unstable, kind of slightly deranged maybe even - you know, Dr. Evil. To what extent do you think their policies can be seen as a rational pursuit of national interest?

SANGER: Well, if you view your rational pursuit in the long term, which means developing an economy, creating jobs for your people, making sure your people are fed, then they have not pursued a wise or rational policy. But if you consider your objectives to be to assure regime survival, to make sure that North Korea remains the Kim family's personal fiefdom, then they've pursued a pretty rational strategy, one in which loyalty is above all, in which even members of the family who challenge the leadership end up getting executed. And under that structure, the North Koreans, for an unstable, irrational regime have played a pretty good game since 1953.

I mean, think about this - every president since Harry Truman has been convinced that the North Korean regime was going to collapse on their watch. And every one of them has been wrong.

DAVIES: So the North Korean regime now, we believe, has a number of nuclear weapons. And it has short and medium-range missiles which might carry a nuclear weapon, right, but does not yet have an intercontinental ballistic missile. Is that right?

SANGER: That's right.

DAVIES: Right. So if they were to achieve that - have missiles which could reach the United States and nuclear weapons and the ability to deliver them, what would that mean to us and to the world order? There must have been a lot of, you know, scenario-planning about this.

SANGER: There's been huge scenario-planning about this. And this all changes dramatically the day the North Koreans drop an intercontinental ballistic missile convincingly 200 miles off the coast of California because, suddenly, we will think that we can be held hostage or one of our cities can be held hostage to whatever happens on the Korean Peninsula or in Asia, even if the North Koreans did something that would not be in their interests like attack South Korea or attack Japan.

Unless we were persuaded that we could 100 percent intercept an incoming missile or several of them, we would be in a situation in which the United States could be blackmailed about the survival of some of its cities by a regime that, you know, has been fodder for late-night comedians for many, many years but would suddenly be no joke.

And I think what President Obama was warning President Trump in those meetings prior to President Trump taking office was, this one is going - is most likely to come a cropper on your watch. And you better pay attention to it soon. And in fact, in the opening month of the Trump administration, they had more meetings on North Korea than any other national security problem.

DAVIES: I want to talk, in a moment, about how President Trump is responding to this. But let's, for a moment, look back at the history here. I mean, this is a nuclear program that has been developing for decades. There have been negotiations. There have been economic sanctions. There have been agreements. Could we have done this better?

SANGER: Yeah, I think we could have. We had a lot of different decision points. And at each one, a succession of presidents, from George H.W. Bush through Bill Clinton and George W. Bush and then President Obama, faced a variant of the same problem, which is - can we entice North Korea to give up this program with the promise of economic development? And failing that, are we willing to go take the risk to take military action to wipe this program out?

And the difficulty in the opening days of that question was that North Korea has had - and still has - a non-nuclear way of destroying Seoul, one of the biggest and most prosperous capitals in Asia.

DAVIES: The capital of South Korea, right...

SANGER: The capital of South Korea.

DAVIES: ...Which is not far from the border of North Korea, right?

SANGER: It is closer to the border - or the northern border of the Demilitarized Zone than Baltimore is to Washington. So the problem has always been that with mortars that are hidden away in the mountains there, there could be such destruction rained across a city of 14 million people or so and of course one of the economic hubs of Asia, that no one really thought it was worth the risk to take out the theoretical threat of a nuclear North Korea.

And so every time we face this issue, American presidents sort of backed down and started up a negotiation. And you'll remember that President Clinton did this in 1994, got a pretty good deal. The North Koreans suspended all of their operations or most of their operations. Then President Bush came in and said well, we believe the North Koreans have been cheating some and finding another way to build nuclear fuel. They were right. They had been. They suspended that entire program. Dick Cheney in particular said we don't negotiate with evil. We defeat it. But then they didn't defeat it. They went off and did Iraq and Afghanistan and got distracted.

And in the second term, over Cheney's objections, started up a new set of negotiations. Those all fell apart as soon as President Obama came in. And in the interim, the North Koreans tested their first nuclear weapon in 2006. It wasn't terribly a successful test. But they've done four others since, and there's good reason to believe, just looking at the satellite photographs, that they're getting ready to do one or two more in the next couple of weeks or months. And with each one, they get better at this. And they get better at shrinking the nuclear weapon to the point that eventually they'll be able to shrink a nuclear weapon to a size that's small enough that they'll be able to fit it in the nose cone of one of those missiles.

DAVIES: A number of countries may use cyberactivities against the United States. What's different about what's happening between the United States and North Korea?

SANGER: You know, we talk a lot about cyberwar these days, Dave. And in most cases, we don't have cyber war. What we have is the use of cyber techniques at various moments against another nation. That's what the Russians were doing when they were trying to disrupt the election and steal emails that ultimately, in the minds of the intelligence community, hurt Hillary Clinton and helped Donald Trump. It's what's happened in cyber theft and so forth.

But with North Korea, we actually have an active cyberwar underway. People don't recognize it as such, but just think about the timeline here. We know from Snowden documents we were up inside their systems during the Bush administration in a fairly classified program with South Korea. We know that the North Koreans attacked Sony and destroyed about 70 percent of Sony's computer systems, a fact many people lost while they were focused on the release of Angelina Jolie's emails or emails about her.

But this was actually a destructive attack. We know the United States has now gone after the North Korean missile systems and that the North Koreans have gone after banks in the international banking system. North Korea is perhaps the prime case of a country that recognizes it can't get into a direct-on war with the United States. It would lose and lose big. But it can engage in sort of daily or weekly or monthly cyberconflict that's just short of war.

DAVIES: David Sanger is national security correspondent for The New York Times. We'll continue our conversation after a short break. This is FRESH AIR.

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DAVIES: This is FRESH AIR, and we're speaking with David Sanger. He is national security correspondent for The New York Times. He's lately been writing about the North Korean nuclear program and about Rex Tillerson, the new secretary of state. So President Trump has obviously been briefed on this threat. Obama warned him this is a very serious issue for him. How much do we know about his thinking on the issue?

SANGER: Well, we know that they have run a series of first deputies meetings in the National Security Council and then at least one principals meeting at which they looked at the range of options. And that's everything from starting up negotiations again, which they're not eager to do because they realize that every time you do that, you end up paying off the North Koreans to stop doing something that they agreed 10 years or 20 years ago to stop doing. So you're - as Bob Gates, the former defense secretary, used to say about North Korea, I'm not going to buy that horse again, right? So they've dispensed with that.

And at least for now, they appear to have set aside the more kinetic options, which is a polite way of saying attacking the North Korean launch sites and nuclear sites in part because the program is so big right now, we don't know where all the North Koreans' launch sites and nuclear sites are. They probably have between 12 and 20 nuclear weapons at this point. And they're smart enough not to keep them all in one place.

And as we discussed before, they have a lot of launch capability that they can hide away and spread out. So at this point, doing an attack of that kind convincingly enough that you would be able to do it and save Seoul, well, it's a pretty big bet. You're really rolling the dice on that one. So they're going back to the old, familiar argument that they're going to get China to go solve this problem for them. And their thinking on this is that it's the Chinese who supply the North Koreans with oil, with much of their trade.

The Chinese don't have an interest in having a nuclear North Korea either. And so they think they can pressure the Chinese to stop this program. That'll be the focus of a lot of discussion when President Xi comes to Mar-a-Lago to see President Trump for the first time in a meeting we believe is going to happen next week. But the White House has not yet announced it formally. So the idea here is get the Chinese to go solve this problem for them. My own view, Dave, is if the Chinese were going to solve this problem, they would have solved it 20 years ago.

DAVIES: What has been China's posture on this issue over the decades?

SANGER: China's posture on this issue over the decades has been let's just keep the status quo. Let's not anybody get excited. If they're going to build nuclear weapons and we can't really stop them, let's kind of look the other way and start an endless negotiation and just keep the temperature low, which is a perfectly good strategy except if the North Koreans get to the point where they actually can reach the United States. And then you've got a much bigger problem.

Why are the Chinese taking this view? Because the Chinese have something they worry about more than a nuclear North Korea. Their biggest worry is a collapsed North Korea, a North Korea in which 20 million plus starving North Koreans pour over the Chinese border looking for work and food, causing a lot of trouble, a world in which the North Korean territory gets taken over by South Korea and that maybe American troops move right up to the Chinese border with the South Koreans.

Although I suspect one of the things that you'll hear from the United States, or at least the Chinese will hear, is don't worry if this scenario plays out, we will keep our troops south of the 38th parallel. We'll keep them in South Korea. You won't be looking at them. But the Chinese have reason to doubt this. And they worry about losing this territory to an ally of the United States. So they'd sort of rather keep the status quo, especially if they don't think they've got enough control to determine who would take over after Kim Jong Un, the current leader.

And then there's the other short-term problem. Let's say you have a collapsing North Korea and there's a scramble for those nuclear weapons. The U.S., South Korea and China may all be looking for them. So could a bunch of North Korean generals or colonels who think the end is near here and they're going to grab one and detonate one just to make a point on the way out. And that could lead to a great calamity.

DAVIES: So if negotiations and financial sanctions haven't worked, if a military strike doesn't seem likely to wipe out the program and would likely spark a retaliation against Seoul, South Korea and China's not likely to do anything very different, I mean, I guess you're left with the cyber warfare option, aren't you?

SANGER: That's right. The cyberwarfare option is the least bad of a series of really, really bad options.

DAVIES: You know, in one of the recent pieces about this in The Times where they noted that the North Koreans had managed to steal money from some international banks with cyber operations, it noted that North Korea itself has so little electronic infrastructure that most of the North Koreans that are engaging in their cyber efforts are actually outside the country. Is that right?

SANGER: That's right. And, you know, they're a fascinating case in the world of cyberwar. And I spend a lot of time thinking and writing about how the dynamics of cyberconflict, even short of war conflict like this, are different from what we're accustomed to. And the advantage goes to a country that doesn't have very many internet connections. So you know, there are probably fewer internet connections and IP addresses in all of North Korea than there are in some blocks of New York City and Los Angeles.

That is a great defense for the North Koreans because they can wreak great havoc on our civilian cybersystems, whether it's the power grid, the cellphone network, internet providers, the financial system. And they don't really have to worry about cyber-retaliation on North Korea because there's not much for us to attack. So we would be then limited to an attack back on North Korea that would be more traditional. And of course if we did that, it could spark that scenario you don't want of the shelling of Seoul.

DAVIES: You know, the other element of the U.S. response here is the president himself who's known to sometimes, you know, trust his gut and make snap judgments on important issues. And in January, when Kim Jong Un announced that they were close to testing an intercontinental ballistic missile, Trump tweeted, won't happen. I'm wondering how that response was regarded by those who follow this issue and what people expect from President Trump as he continues to confront this.

SANGER: Well, I think their hope is that President Trump will discover that the North Korea problem, like the problem of replacing Obamacare or cutting taxes or funding NATO, is a lot more complicated when you get down in the Situation Room than it seemed when you were out on the campaign trail. On the campaign trail, it's pretty easy to say, you know, we'll teach these guys. They're a little pipsqueak country.

And then you get down in the Sit Room, and you start running through all the scenarios that we just discussed. And you say - wow, this is really hard, and the options are really bad. It's not that the United States wouldn't win an outright conflict with North Korea. Of course we would. The problem is how much damage happens in those first 24 hours or 48 hours before you win and what that would do to Asia and what the repercussions of that would be.

So that's why I think that the cyber option that President Obama seized upon is so attractive, as cyber frequently is to presidents. So here you go back again to the Iran example. In the days leading up to President Obama's decision to accelerate the U.S. attacks on Iran - the cyberattacks in 2009, what else was going on? We had Israelis saying we may bomb the Iranian sites if we think Iran is getting too close to a bomb. And the Americans were saying, slow down there. You do that; we have another war in the Middle East. So the cyber option looked like a good way to buy some time. But that's all it does. It only buys you time.

In North Korea, it's harder to say that we have a fixed outcome. We can slow their program. But toward what end? Because there's no price in the world that the North Koreans are willing to take to sell off their nuclear program. If North Korea gave up its nuclear program, it doesn't really have a way to go survive in the international community. And the North Koreans know it, and they wouldn't believe us, even if we assured them that we would keep them alive.

DAVIES: Well, David Sanger, good to have you back. Thanks so much for speaking with us.

SANGER: Dave, it's been terrific to be back with you. And thanks for giving me the chance.

GROSS: David Sanger is The New York Times national security correspondent. He spoke with FRESH AIR's Dave Davies who is also WHYY's senior reporter. After a break, Maureen Corrigan will review a new novel about two boys who side with their father in a custody battle. The father wins. Things do not go well. This is FRESH AIR.

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