What's next in the Korean nuclear crisis?

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Hello, and welcome to World Weekly from The Financial Times. I'm Gideon Rachman.

Today, we're looking at the nuclear crisis on the Korean peninsula and getting the views from Seoul and Washington. On the line from the South Korean capital is our correspondent there, Bryan Harris. North Korea's just tested what it claims is a hydrogen bomb, so are the South Koreans frightened?

The short answer is no. Living in Seoul, citizens here have lived with this threat close to 70 years are well acclimatised to North Korea and its array of threats and verbal barbs that it's thrown us. Over the years, regularly, North Korea says it will turn Seoul into a sea of fire. And at this point, Seoul-ites, citizens of Seoul, have come to the conclusion that they probably won't do it anytime soon. So that must be in terms of the latest North Korean threats. It is very calm.

I think where there may be some concern is about US president Donald Trump and some of his rhetoric. South Koreans are concerned that he may not be committed to the peninsula and that the North's development of a nuclear weapon may threaten the US-Republic of Korea alliance.

Yes. That seems to be the big difference this time. How big a gap has actually opened up between Seoul and Washington? Donald Trump's even gone as far as accusing the South Koreans of appeasement of North Korea.

Indeed. And this was a serious and embarrassing dressing down for a longstanding US ally. The authorities here would never say it, but in private, they will say that it is embarrassing. Also, it was unnecessary, because Trump didn't need to make these comments. And in the long run they could prove counterproductive. A much simpler approach would would have reassured South Korea. South Korea is facing these threats from North Korea regularly. So if he had reassured them, it would have helped to solidify the alliance and further deter Pyongyang.

Now, now Pyongyang sees the beginnings of a crack, of a divide. And it will seek to exploit that divide going forward. But not also Pyongyang, also China. China has an opportunity here as well.

So what does the South Korean government expect to happen now? Do they expect more tests from North Korea?

I think yes. I think there's a sense that North Korea will continue with its provocations. There is an expectation that weekend, especially on Saturday, that North Korea will launch a ICBM, a long range missile, standard trajectory. They could be firing into the North Pacific or potentially down towards Guam, which would be obviously a big deal for the Americans. This is as North Korea continues to develop and hold a missiles programme. There's some speculation that once North Korea has mastered these technologies and it has proven the ability to launch these missiles, it will cease these provocations. But to get to that point, they would need to test a long-range nuclear missile, which would, of course, be a hugely inflammatory move which would rile the global community more so than a regular rocket test or even a nuclear weapons test at home in North Korea.

It's an impossible question, I know, Brian, but how do you see this all ending?

I think the status quo will continue. The strategic calculus on the Korean peninsula hasn't changed. And the US, South Korea, China, even North Korea, are all facing the same structural constraints. A war on the peninsula would leave millions and millions of people dead, both in North and South Korea. Of course, nobody wants that to happen. Despite President Donald Trump's rhetoric of all options are on the table, it looks very unlikely that he will be able to use the option which he's threatened, which is offensive war. And that means we'll continue as is, with continued provocations and potentially lethal, but small-scale interactions across the DMZ. That hasn't happened for many, many, years.

That was Bryan Harris, Seoul. For the view from Washington, we now turn to our bureau chief there, Demetri Sevastopulo. Demetri, is there a sense of crisis around the Korean situation in Washington?

I think there is a sense of crisis building. I mean, I remember during the campaign trail, very few American voters were talking about North Korea. Now, North Korea is on the television screens, on the news, almost every day. People are starting to ask-- ordinary people are starting to ask, is it possible that North Korea could hit the US with a nuclear weapon, a long-range missile?

So I think that the level of crisis has definitely risen because of the rhetoric and the actions coming from North Korea. But it's also risen because of what Donald Trump has been doing. The kinds of tweets he's been sending out. Talking about raining fire and fury on North Korea if it keeps threatening the US. Also raising questions about its alliance with South Korea if it appeases North Korea. So there's a lot of tension on both sides. And I think this is, without a doubt, the most serious foreign policy crisis that Donald Trump has faced in his first eight months into office.

And one of the things that Obama was criticised for was drawing a red line in Syria and then not enforcing it. It looks to me as if Trump has drawn a very big red line with North Korea by saying that they will not develop a nuclear weapon that can threaten the continental United States. Is he really able to deliver that?

Well, that's the big question. I think many people would say he's not. But while the US doesn't want to publicly concede that North Korea is, in effect, a nuclear weapon state, that's what it's become. The only question now is whether North Korea has developed the capability to miniaturise a nuclear warhead so that you could put it on top of a missile. And whether the warhead would survive re-entry into the atmosphere if it was fired towards the US. Everything else, the North Koreans have demonstrated the capability to do.

So I think it's difficult for Donald Trump to draw a red line like that, because at what point do you decide that North Korea can do everything? Unless you see them test every possible part of their system, you don't actually know 100% whether they can do it. So it's difficult to draw a red line, I think. And it would be a huge decision to preemptively attack North Korea to try and stop them from shooting a missile towards the US.

I mean, it's a very difficult policy problem for whoever. But it does seem like Trump's been thrashing around a bit. So that back in March, he was very much looking to China to deliver North Korea. Then there've been tweaks which signal disillusionment with China. There've been the fire and fury comments, but then backing off those a little bit. There's the talk of a close alliance with South Korea and then suddenly accusing South Korea of appeasement of the North and even possibly talking about repealing a trade deal with South Korea. Do you get a sense that there's a coherent strategy behind all of this? Or does this just reflect the kind of lack of good options?

Well, I think it's a little bit of both. It definitely partly reflects the lack of good options. But behind the scenes, I think the Pentagon and the State Department have-- and General McMaster, the White House National Security Adviser-- they have a strategy, which is to increasingly tighten the economic screws on North Korea, both directly, through international sanctions at the UN, and as much as possible, through action that they want China to take. For example, they would like Beijing to cut off oil exports to Pyongyang.

At the same time, they're backing that up with what you would call gunboat diplomacy. You've had bombers, fighters flying over the DMZ, over the Korean peninsula, to send a message to Kim Jong Un-- A, don't threaten the US and B, If you do, these are the kind of weapons we're going to inflict on you. And I think that's all deliberate. And they're trying to be very calculated and measured in how they balance those two things. The difficulty is that Donald Trump sends out a tweet and he tends to take the most extreme of those positions, and suggests that the US is on the verge of attacking North Korea, which then forces some of his officials to kind of walk things back a little bit, which then, in turn, undermines their own strategy. So I think the president, you know, he's trying to help on the one hand, but he's complicating life for his officials.

And there's also a question as to whether his tweets are really aimed at furthering foreign policy goals, or whether he's just talking to his base and saying to them, I'm a strong man. I'm not going to be pushed around. Kim Jong Un better watch out. And we don't really know the answer to that question.

One specific thing which we hear hints of-- and I'll be interested to know what you hear from your contacts in the intelligence community and so on-- is the sense that North Korea has developed much faster than people anticipated. And that they must be getting some sort of foreign help. They can't be doing all this technology indigenously. Is that a discussion that's taking place in Washington?

I think-- I mean, they've traditionally gotten a lot of help from Russia and elsewhere. And I've been told that in recent years, the help from outside has dried up a little bit. But they still get technical help from scientists in other countries, if not directly from the state. But it's certainly true that over the last few years, North Korea has outpaced the US in terms of what American officials thought they would be able to do during what time frame. But frankly, that's something that's happening with China, as well. You know, every year the Pentagon puts out a military report on how China is doing. And every year, they concede that China has gone further than they expected it would. I think the same thing is happening with North Korea.

But we've now reached a point within eight months of Donald Trump's presidency where what Barack Obama told him was going to be a big issue has become a really big issue, because it's fired two ICBMs that have a theoretical range to hit at least the west coast of the US. So that has completely changed the dynamic, I think. American officials are now having to view this in a very different way.

OK then, just to round it off. I mean, we started by talking about this growing atmosphere of crisis within the US, within Washington. How possible is it for this situation to continue to maybe even fizzle out? Or will this in the way of crises actually have to reach some kind of dramatic resolution, whether it is a military conflict or some big diplomatic breakthrough? How long can we go on at the current level of provocation?

Well, at the moment, Kim Jong Un has shown absolutely no signs of slowing down. If anything, he's speeding up to get to the finish line to prove to the Americans and the world that he has a nuclear deterrent. Essentially, he can hold America at risk because he has nuclear warheads that can reach the US. I don't think that's going to change.

At some point, will he conduct a test, for example, send missiles towards Guam, to show that he genuinely has the reach that he says he has? If he does that, that probably changes the calculus. I mean, Trump has said that he will respond very heavily if that happens. I think that will be a huge gamble. But, you know, barring that, it's difficult to know what the US can do, except continue on the current path.

Now, there are some people saying the US needs to start thinking about preventive war, an attack on North Korea to destroy its nuclear facilities and its other weapons. But many people say that's very, very difficult to do, because the US doesn't know where all the weapons are. There's a huge number of conventional weapons that would need to be destroyed. Estimates are that hundreds of thousands, if not millions, of South Koreans will be killed in a retaliatory attack from North Korea if the US struck North Korea first. So I think the risks are incredibly high.

Thank you very much indeed, Demetri. And thanks also to Bryan Harris, Seoul. That's it for World Weekly this week. Until next week, goodbye.