♪ ♪ >> NARRATOR: Tonight... >> If the United States is forced to defend itself or its allies, we will have no choice but to totally destroy North Korea.

(rocket engine hisses and roars) >> NARRATOR: As tensions between North Korea and the United States mount, a rare glimpse inside the regime... >> The half-brother of North Korea's leader was assassinated using the most toxic nerve agent ever created.

>> NARRATOR: The story of a murder that leads back to Pyongyang... >> People that say that this was a botched job are not thinking like North Korean intelligence operatives.

They're not thinking like killers.

>> NARRATOR: What it reveals about Kim Jong-Un... >> In order to survive, he had to conduct politics inside the regime.

And politics inside North Korea is a blood sport.

>> Kim Jong-Un is ruthless, he's brutal, but he's not suicidal.

He's not irrational.

He's very shrewd and calculating.

I think he has a plan, he has a goal, which is to complete the nuclear program.

>> NARRATOR: And the capabilities of his regime.

>> He's managed to generate enough precision, technical acuity, and money in order to build a nuclear missile program that poses a genuine threat to the United States.

>> We're truly in some uncharted territory.

The game that they're playing has incredibly high stakes.

>> NARRATOR: Tonight on "Frontline:" "North Korea's Deadly Dictator."

♪ ♪ >> He was always like in a plane going one place and the other.

I was even surprised that he was going to Kuala Lumpur.

Because at the time I thought that he was in... in Paris.

♪ ♪ >> NARRATOR: It's 9:00 on the morning of February 13, 2017.

(plane whirring) An ordinary-looking man arrives at Kuala Lumpur airport, terminal two.

>> I mean basically it's a huge terminal.

Once you're inside it's like a maze.

There's so many types of people from all walks of life.

>> NARRATOR: The man is checking in for an Air Asia flight to the Chinese territory of Macau.

>> He went to one of those self check-in kiosks to get his boarding pass.

That's when he was approached by the two ladies, they sort of flanked him from left and right.

>> NARRATOR: Two women appear to bump into him.

One appears to put a cloth over his mouth.

Then the women walk calmly off and no one else seems to notice.

The whole thing has taken less than five seconds.

>> I think he immediately felt the effect.

Probably less than a minute after he was attacked.

That's why when you see the CCTV in front of the entrance where he first made contact with the policeman, he was rushing through something.

But, since it happened so fast, they didn't know that this is a serious matter.

>> By the time he was walking towards the clinic, he was already dragging his feet.

He was sweating profusely.

His coordination went haywire.

He had a minor seizure and then he defecated.

He died in the ambulance, by 11:05, I think, he was pronounced dead.

>> NARRATOR: The dead man was traveling on a North Korean passport with the name Kim Chol.

But as the pictures went around the world, it soon became clear who he really was: Kim Jong-Nam, the half-brother of North Korea's dictator, Kim Jong-Un.

>> The assassination of Kim Jong-Nam was not only a surprising event, it was carried out in such a bizarre manner, that it's hard to imagine any other country on earth other than North Korea carrying this thing out.

The way that I see North Korea is an elaborate soap opera.

It is ruled by individuals, it is not ruled by institutions, and I think the assassination of Kim Jong-Nam is a very personal thing inside North Korea and inside the heart of Kim Jong-Un.

>> North Korea is living in a world unto itself.

The last few months of the U.S. North Korean relationship have been some of the most tense in the entire history, going back to 1953, the end of the Korean War.

If you want to understand what's actually going on in Pyongyang, if you want to know why they make the decisions they make, one of the things you have to understand are these rare moments when the palace opens its doors inadvertently and lets you in.

And one of those moments, perhaps its most spectacular moment, was the assassination of Kim Jong-Nam.

>> NARRATOR: North Korea has been ruled for seven decades by the Kim family dynasty.

They have created a fearsome police state accused of systematic human rights abuses.

Kim Jong-Nam was the oldest son of Kim Jong-Il, who ruled North Korea for 17 years.

>> NARRATOR: His mother was Kim Jong-Il's mistress, a famous North Korean actress.

>> His mother was number one film star in my generation.

And his mother was a married woman with a daughter.

Every North Korean people knew his mother's name, Sung Hae-Rim, very popular lady.

So Kim Jong-Nam was not the son by official marriage.

>> NARRATOR: The boy's existence was kept a secret in North Korea.

But he was brought up in luxury, like a prince.

>> Kim Jong-Nam's childhood was very, very cloistered.

The ceilings in the house were so high they needed to bring in scaffolding to dust the lights.

There was always the off chance that Kim Jong-Il would be dining with Kim Jong-Nam, and so somebody literally goes through a sack of rice and pulls out any irregular, any broken piece of rice.

You're talking perfect bag of rice sent to Kim Jong-Nam's house.

>> He was a bit like his father.

Artistic, I think.

And Kim Jong-Il doted on Kim Jong-Nam.

And when his family, his mother, aunt, et cetera was-was planning to send him away for education in foreign country, we know that Kim Jong-Il cried.

He wept and he remonstrated, protested against their plan.

>> NARRATOR: Despite the dictator's objections, the women prevailed.

Kim Jong-Nam was sent off to school in Moscow, and then Geneva.

>> My earliest memories of Kim, we were, I think, around 15.

One day we entered in class and we saw that guy who looked like an adult for us.

We didn't know at the time that he was the son of-of Kim Jong-Il.

We...

I think we didn't even know he was Korean.

I mean, we didn't really care at the time, but we saw him arrive with his little attaché case, a black suit, his hair done just like his dad, you know.

>> Back then I called him Lee.

I called him Lee, that's what he told us his name was, Lee.

I think that's what he showed us on his driver's license, I'm not sure.

Because we loved the fact he had a fake driver's license, we thought it was fake because he was obviously 15 in our class, but his license said he was 18, and he was driving, and we loved that.

Very, very jealous at the time, you know, as all young boys would be.

>> NARRATOR: Released from his secretive existence inside North Korea, Kim Jong-Nam got his first taste of life in the West.

>> I remember too it was the beginning of, like, cameras.

And he was always taking his camera to school and filming everybody.

Today your phone has a camera, but at the time it-it was something special to have your own camera.

>> I think he was just happy to take glimpses of life, you know, to photograph, so maybe it was interesting for him to film us carefree.

>> NARRATOR: But in 1988, that carefree life came to an end.

The 17-year-old was summoned back to North Korea.

His father revealed him to the rest of the family, and analysts believe he was prepared for leadership, and exposed to the regime's brutality.

>> During the 1990s, as North Korea's economy starts to sort of deteriorate, the party authorities start to crack down on what's called asset stripping, or the selling of scrap metal to China and to other people.

Buses of security agents would arrive in a town, a factory town, overnight.

They would sit there and then they would start picking people to execute publicly.

Kim Jong-Nam was involved in that, and he was involved in attending public executions of party and economic officials.

>> I don't think he had the ice in his veins necessary to do what it took to-to... you know, it's not easy to hold a country together the way they're holding a country together, you know.

It's a certain skill set you need that he didn't have.

He was a nice boy.

>> He's got different ideas and he starts to become a rebellious, you know, teenager or rebellious 20-year-old.

And this does not really sit well with Kim Jong-Il.

>> You're a prisoner in a gilded cage, you have everything but you have no freedom, and he wasn't happy, he wanted to leave.

And he distinctly told me he had to ask his father to leave.

>> NARRATOR: Eventually, his father let him go, but only as far as neighboring China.

>> Strange reports that the estranged half-brother of Kim Jong-Un is dead and possibly murdered.

>> It looks like something straight out of the pages of a spy novel.

North Korean royalty, Kim Jong-Nam, the estranged exiled half-brother of leader Kim Jong-Un, falls ill... >> NARRATOR: Within days of the murder, Malaysian police captured the two women who carried out the attack in the airport.

>> Both women, police say, practiced the attack several times before last Monday's assault.

>> NARRATOR: It was becoming a huge international story.

>> There was an adrenaline rush to it, it was quite addictive, I have to admit.

As far as the police are concerned, it was pretty clear cut, everything was on CCTV camera, they had done the act, that was for sure.

>> NARRATOR: But the story was about to take its first sensational twist.

One of the killers, 25-year-old Indonesian Siti Aisyah, now gave her version of what happened.

She claimed that six weeks earlier she had met a Japanese man called James.

He'd offered her a job: work on a hidden camera prank show for YouTube.

>> When she met this so-called James, she was asked to watch another lady to see how the prank was being played.

And thereafter she was asked to play about three pranks, and after the prank she was paid a certain sum of money.

And the next day again she was taken to the airport where, again, they played about three pranks on-- at the arrival area.

>> NARRATOR: With James, Siti said she carried out more than 20 filmed pranks on people she thought were unsuspecting members of the public.

Siti posted this video on Facebook.

>> When we go... turn off.

>> NARRATOR: The man she knew as James seemed a little camera shy.

>> Now Siti was a social escort, and she was also a masseuse, and her income wasn't very high, and she didn't quite like the job that she was doing.

And when she was introduced to play these pranks, she was quite excited about the whole thing.

She even told all her friends about the pranks that she played because she actually believed that this could have been her new career.

>> NARRATOR: The second woman involved in the attack was 28-year-old Doan Thi Huong.

She came from over a thousand miles away in Vietnam.

Doan also said that she had been rehearsing pranks.

>> NARRATOR: Siti claims she never met Doan before that day in Kuala Lumpur airport.

In custody, they were charged with murder, which in Malaysia is punishable with the death penalty.

>> Now Siti did not know that Kim Jong-Nam died on the day of the incident.

She only realized after the police came to her.

We told her what actually happened now that she had been charged for a case, which is punishable with death, and then she realized how serious the matter was, and then she broke down, yeah.

>> The representatives of the two ladies are standing firm on the fact that these ladies were deceived.

On the other hand, somebody has to be held accountable for the murder.

You cannot plead ignorance in your defense.

Were they victims?

Were they tricked into believing that they were part of a show?

Or were they willing participants in the plot?

That the court will have to decide.

We will just wait and see.

♪ ♪ >> NARRATOR: By the late 1990s, Kim Jong-Nam appeared to be living the life of an international playboy.

Based in Macau-- known as the Las Vegas of China-- there were reports that he had more than one wife and several children.

>> On the whole, he was more like a tycoon without taste for hard work of a typical tycoon.

He was a kind of playboy, typical bourgeoisie playboy mentality.

And he never lacked the money.

Lots of money to spend.

Lots of money, but he still seemed to be wanting more money.

>> NARRATOR: So how did Kim Jong-Nam fund this lifestyle?

There are clues in Kuala Lumpur, Malaysia.

When he was here, Kim Jong-Nam would often eat at this Korean restaurant.

>> (speaking Korean): >> (speaking Korean): >> NARRATOR: Though he'd been living abroad, Kim Jong-Nam hadn't cut ties to North Korea.

Analysts suspect he was running an international business network, generating funds for the family.

>> (speaking Korean): >> Kim Jong-Nam was involved in a whole host of illicit businesses that North Korea conducted.

He could have been involved in the nuclear missile arms trade, he could have been involved in currency counterfeiting, he could've been involved with some drug smuggling.

So it was unclear exactly what he did for a living, but we know that he was involved in this whole host of things that... particularly that involved money and currency that goes back to North Korea.

>> NARRATOR: By 2007, Kim Jong-Nam was a wealthy wheeler-dealer, believed to be playing a key role in his father's regime.

Nearly a week after the killing, the Malaysian police announced a major breakthrough.

>> As investigation progresses, four suspects has been identified, which could assist us very much on the investigation.

And I can confirm today that they have left our country the very same day the incident happened.

Yeah.

Thank you very much.

>> NARRATOR: The two foreign women hadn't been operating alone in Kuala Lumpur Airport.

This came as no surprise to Kim Dong-Sik, a former North Korean intelligence officer who defected to South Korea.

>> (speaking Korean): >> (speaking Korean): >> NARRATOR: The CCTV footage from the airport showed at least four men whom authorities believed were North Korean operatives.

>> NARRATOR: The key figure was a man in a gray-striped shirt identified by police as 57-year-old Ri Jae-Nam.

>> Ri Jae-Nam is a long-time North Korean intelligence operative, somebody that's got extensive contact overseas.

>> NARRATOR: Ri Jae-Nam appears to coordinate the operation from beside a pillar.

As Kim Jong-Nam looks at the departure board, he couldn't have known he was now surrounded by North Korean agents.

Then the two young women separately approach their target.

>> (speaking Korean): >> NARRATOR: As Kim Jong-Nam enters the clinic, another man suspected of being a North Korean agent follows close behind.

>> (speaking Korean): >> NARRATOR: Before Kim Jong-Nam was confirmed dead, the suspected North Korean agents had already made their escape.

According to immigration officials, they boarded a plane and flew to Jakarta, then Dubai, and ultimately onto Pyongyang, the capital of North Korea.

It looked like the perfect hit.

>> The recruitment of two foreigners was done so that they could remove their fingerprints from this assassination, and essentially point the finger in another direction.

I suspect they were expecting these women, because they didn't use gloves, to die of this chemical.

But the women went to the bathroom very quickly, washed off the chemical, and were able to survive.

>> NARRATOR: But within days, the Malaysian police were pointing the finger firmly at North Korea.

It brought complete denial.

>> It has been seven days since the incident, but there is no clear evidence on the cause of the death.

And at the moment we cannot trust the investigation by the Malaysian police.

They pinned the suspicion on us and targeted the investigation against us.

Now there are so many rumors spread to the public to defame the image of the Democratic People's Republic of Korea, the Malaysian police should bear the full responsibility for that.

Thank you.

This is my all comment.

Thank you.

(reporters clamoring) >> NARRATOR: The killing in Kuala Lumpur was the latest chapter in the bloody history of the North Korean regime.

It traces back to 2008, when the dictator Kim Jong-Il suffered a debilitating stroke.

He had to choose a successor from among his children.

He had at least two daughters, but they were ruled out because they were women.

He once reportedly complained that all his sons were "idle blockheads."

Kim Jong-Nam-- his oldest-- was now seen by many as too Westernized.

>> How's your relationship with your brother?

>> NARRATOR: There was a mysterious second son.

Little is known about him, other than that he is an Eric Clapton fan who pops up at concerts around the world.

There was one more option.

>> There's this younger guy, he's 23, 24 years old, his name's Kim Jong-Un, starts to get the similar kind of jobs that Kim Jong-Nam got, because this is a family business, and so you're gonna get a job.

The Kim family-- they trust you, they trust family members, and so Kim Jong-Un's career kind of starts, and that's the best option, because that's all they know, that's the life they know, is the strongman dictator.

>> NARRATOR: With Kim Jong-Il's health failing, the youthful Kim Jong-Un was anointed successor.

He now needed a crash course in dictatorship.

(weeping) But this training was cut short.

In December 2011, Kim Jong-Il died.

Still in his 20s, Kim Jong-Un was now declared Supreme Leader.

>> There's a lot of mystery surrounding how Kim Jong-Un got the job; I mean, there's a lot of mystery around a lot in North Korea.

But one of the things that's become clear is that Kim Jong-Un essentially won a battle for succession, and he won it on the basis partly of attitude and aggression.

(cheers and applause) When Kim Jong-Un became the successor to Kim Jong-Il, that came with it a tremendous amount of expectation and responsibility.

There had never been a third generation communist dictatorship.

A lot of people predicted it wouldn't last.

>> Kim Jong-Un did not have decades to build his power base within the regime.

He has only had a few years to do something that it took his father 30 years to do.

In order to survive, he had to conduct politics inside the regime.

And politics inside North Korea is a blood sport.

It is not something for the weak of heart.

>> NARRATOR: Within months of assuming power he began a brutal purge of senior officials-- anyone who might have challenged him.

The second most powerful man in North Korea was Kim's uncle Jang Song-Thaek.

In December 2013, he was executed.

Kim Jong-Nam was another threat to the new leader's legitimacy.

He had gone public with his criticism of the succession.

>> (speaking Japanese): >> NARRATOR: Between 2010 and 2012, Kim Jong-Nam exchanged almost 150 emails with Japanese journalist Yoji Gomi.

In them he criticized the decision to transfer power to a third generation of the Kim family.

And he suggested that the new leader lacked experience and would end up as a "mere figurehead."

He also criticized how the country was being run.

Kim Jong-Nam's experience of living in China had persuaded him that North Korea should open up and introduce Chinese-style reforms.

>> (speaking Japanese): >> (speaking Japanese): >> NARRATOR: Less than a month after Kim Jong-Un came to power, Yoji Gomi published the emails.

It was a stunning public insult to North Korea's new dictator.

>> Kim Jong-Un has to make a decision whether he let his half-brother, wandering around the world from time to time meeting foreign journalist and saying negative, you know, words against Kim Jong-Un's leadership, or he should eliminate the physical existence of Kim Jong-Nam.

>> According to some decent intelligence sourcing, there was a standing order as of 2011 or 2012 to take out undesired members of the ruling family.

And so this is when people in North Korea's intelligence services get a little creative.

Kim Jong-Nam was living on borrowed time.

This was on a narrow list of possibilities as to how Kim Jong-Nam's life was gonna turn out for him after his half-brother succeeded in North Korea.

>> NARRATOR: Kim Jong-Nam began to keep a lower profile.

It was becoming harder for him to travel to and from North Korea and make money.

♪ ♪ By early 2017, he'd had enough.

>> Three or four days before he died, he text me a message saying, "I'll see you in Geneva.

I'll be back in three days."

He was, like, coming back to Geneva to search back all his youth, like, part of a time where we had nothing to think about, nothing to be afraid of.

>> NARRATOR: Kim Jong-Nam told his friends that he wanted to move to Europe and change his citizenship-- in essence, defecting to the West.

>> I think he let his guard down somewhat in Europe, he felt more safe and more secure here, especially in Switzerland.

Was he worried?

Yeah, would he be talking about moving to Europe if he wasn't slightly worried?

Probably.

>> It's not easy to live the life he lived.

Okay, maybe he had a bit of money, we don't even know how much he had.

He was very secret about it, but money's not everything.

I mean, if you cannot live freely your life, then I'm sure, like, something breaks inside of you.

>> NARRATOR: Moving to Europe and defecting could have posed a major threat to Kim Jong-Un's regime.

>> From foreign intelligence services' perspective, this is somebody that you want to get to know.

So, I'm sure CIA would have tried very hard to recruit him.

Ultimately, I think Kim Jong-Un was afraid that should hostile powers like United States, or maybe even China, one day want to have a change in regime, that they could put Kim Jong-Nam as head of that new leadership in North Korea, because of course Kim Jong-Nam has legitimacy.

>> (speaking Japanese): >> (speaking Japanese): >> Last week at Kuala Lumpur airport, someone chose to attack Kim Jong-Nam.

Today, we learned what killed him.

And it's even more shocking.

>> ...now determined that a chemical weapon was used to assassinate North Korean leader Kim Jong-Un's half-brother.

>> NARRATOR: The next revelation from the Malaysian police took the story to a new level.

>> A press release was sent out to media outlets from the Inspector General of police, saying that his cause of death was due to something known as VX agent, which was completely new to us.

It sounded like something out of a spy novel.

>> The chemical that we discovered which caused the death is VX...

Which is a lethal weapon registered under the... registered as a chemical weapon.

>> I recall that on Monday morning I got a call from our Director General's office.

Apparently we had received a note verbale from the Malaysian embassy here, asking for the OPCW's assistance, and they wanted some technical assistance, they wanted some advice from me, some reference materials and whatnot.

>> NARRATOR: The Organization for the Prohibition of Chemical Weapons confirmed the findings about what killed Kim Jong-Nam.

>> VX is a nerve agent.

It's actually the most powerful nerve agent that's known to date.

It's about ten times more powerful than sarin, about 300 times more powerful than mustard gas, and about 5,000 times more potent than chlorine, so it's really toxic.

It takes about ten milligrams to kill an average adult person.

Now, ten milligrams is just a fraction of a drop, so it doesn't take very much.

It looks like a horrible way to die.

You basically suffocate, you-you convulse, you're jerking around.

It's not pleasant at all.

>> Why use a chemical VX nerve agent, in a public international airport?

So many things could have gone wrong.

One of the ladies could have kind of just done it wrong with somebody else, just by tripping.

So many accidental possibilities.

>> You needed something that would kill him, but that you would have the lag time or the delay in the death that would allow the North Koreans to get out of the country.

If you slit his throat, you, one, can't do it in a public place, two, you can't use foreign agents that you have duped into thinking that this is some sort of a game show.

>> And I think Kim Jong-Un wanted to make a point to any would-be rivals, potential opponents, defectors out there, saying, "I can kill you in any manner."

So, I think he wanted it to be public, he wanted the whole world to know.

>> NARRATOR: VX is banned under the International Chemical Weapons Convention.

But analysts have long been convinced that North Korea is manufacturing it.

>> North Korea has a long-standing chemical weapons program.

They've had this program for a number of decades, it's quite large, it's on a military scale, it was designed for war fighting.

North Korea's likely the only country currently in the world today that has active chemical, biological, and nuclear weapons programs, and possibly even the ability to deploy all three.

That really puts them in a league of their own, in terms of current capabilities.

>> Big story here, keep an eye on it.

North Korea firing four ballistic missiles toward the Sea of Japan early Monday morning.

>> Tonight, Kim Jong-Un could be one step closer to threatening America with a nuclear-tipped missile.

The ballistic missiles his regime just test-fired... >> NARRATOR: Three weeks after the assassination, Kim Jong-Un had another point to make.

>> (speaking Korean): >> NARRATOR: He began the most intense period of missile testing in North Korea's history.

(explosions) In the months since the assassination, Kim Jong-Un has launched more missiles than his father launched during his entire reign, developing North Korea's ability to reach farther and farther distances.

>> North Korea is now very close to completing their program, nuclear program, perfecting their nuclear arsenal, having an ability to attack United States with nuclear-tipped ICBM.

And now Kim Jong-Un is trying to complete this program, and he's very, very close to doing that.

So we are at the final stages and this is why we're uniquely in a very dangerous time period.

>> What we're seeing now is North Korea trying to break out.

What do we mean by that?

To go from a country that simply has the ability to produce a nuclear weapon, to a country that can field a nuclear weapon, that can deliver it, that has a stockpile, a reasonable sized stockpile-- we believe anywhere by public estimates 30 to 60 nuclear weapons.

They're clearly very close to the delivery capability, their actual weaponization and miniaturization of their nuclear warheads has progressed substantially.

Can they put all that together perfectly yet?

We don't know, but nobody really wants to test the proposition.

>> NARRATOR: In early 2017, President Trump had informed the world on Twitter that he would not allow North Korea to complete its nuclear program.

(explosion) But on the fourth of July, Kim Jong-Un took a significant step forward.

He launched a missile which could have reached Alaska, a so-called Independence Day "gift" for the quote "American bastards."

>> (speaking Korean): >> On the fourth of July, North Korea achieved a major milestone in the development of its missile capability.

What they did was that they fired an ICBM, an intercontinental ballistic missile, that was capable of reaching the United States.

They fired it way up into the atmosphere and it came down, so it actually only fell into the Pacific.

But what they discovered as a result of that was that they now had the ability to menace the United States with a weapon.

That was a threshold that, frankly, the American intelligence community never thought they were going to reach as soon as they did, and certainly a lot of analysts were surprised.

From that point on, the United States had many fewer options that they had before; they were now dealing with adversary that was capable, in theory, of putting a nuclear weapon on the continental United States.

>> North Korea best not make any more threats to the United States.

They will be met with fire and fury like the world has never seen.

He has been very threatening, beyond a normal statement.

And as I said, they will be met with fire, fury, and, frankly, power, the likes of which this world has never seen before.

Thank you.

>> I arrived in North Korea a little over a week after Donald Trump began to escalate the rhetoric from the United States.

And when I arrived, I was spending time with North Korean government officials whose job it was was to try to assess, and analyze, and understand the United States.

And they were mystified, frankly; they were just befuddled.

This was not the United States they'd dealt with before, they couldn't figure out what he was saying, they couldn't figure out if he was trustworthy, and they couldn't figure out if he was serious.

(man shouting on loudspeaker) >> NARRATOR: The day after President Trump's threat to unleash fire and fury, North Korea staged a show of defiance in Pyongyang.

(crowd chanting) >> North Koreans have themselves told me that they are willing to use nuclear weapon, but only when they feel truly threatened.

What I'm concerned about is for North Korea to miscalculate and misunderstand our intentions and think an attack is coming, or regime change is coming when we're-we're not doing that.

And this is a problem when there's a lot of bluster with very heightened rhetoric of "fire and fury" and "locked and loaded" and so on, because it could lead North Koreans to miscalculate.

>> NARRATOR: In this propaganda video released two weeks later, North Korea threatened to launch a strike on America's Pacific base of Guam.

>> One of the biggest, hardest questions facing the United States and other countries is why, why does North Korea want a nuclear weapon so desperately, and why is it willing to give up so much in order to achieve it?

There is one school of thought which says that they fundamentally just want self-defense.

They looked at what happened to Saddam Hussein, Muammar Gaddafi and they decided that will never be us, we will never give up our weapons program, and therefore nobody will be able to attack us.

But there's another view, and that view is that ultimately they want nuclear weapons in order to achieve what has always been North Korea's objective, which is to bring South Korea to its knees, and to drive the United States off the peninsula.

>> I think Kim Jong-Un wants to prove that he's a legitimate leader.

And nuclear weapons program is certainly part of that.

And by perfecting and completing this program that his father and grandfather have pursued for the course of many years, he will prove to the Koreans that he's a true leader, a strong leader who can be defiant against the United States.

(beeping) ♪ ♪ >> NARRATOR: But then, North Korea toned down its rhetoric, announcing it was putting its plans to hit Guam on hold.

For President Trump, this was a sign that his approach was working.

>> And you see what's going on in North Korea.

All of a sudden, I don't know, who knows, but I can tell you, what I said, that's not strong enough.

Some people said it was too strong; it's not strong enough.

But Kim Jong-Un, I respect the fact that I believe he's starting to respect us.

I respect that fact very much.

Respect that fact.

(beeping) (rocket fires) >> NARRATOR: Within days, North Korea launched one of its most provocative missiles yet.

It passed over Japan's populated island of Hokkaido, flying for about 1,700 miles, almost the same distance as it would take to reach Guam.

>> The Trump administration has what we would consider sort of a classic dilemma.

They have only choices of bad options.

We can dramatically increase the pressure, economic and otherwise, to see if we can pressure North Korea to the negotiating table.

Or we can choose to treat North Korea as a country that has nuclear capabilities and try to develop a more effective and more stable deterrence relationship with them.

Or we can consider military options, to try to pre-emptively degrade their nuclear capability.

Of course that's profoundly risky, and would likely trigger a broader-scale war, which would bring considerable destruction.

>> If the U.S. were to launch military strikes against North Korea, to try to take out the nuclear program, this could cause North Korea then to react towards South Korea-- bombing Seoul, artillery strikes against Seoul-- which then could unleash an escalatory ladder that no one could find an exit ramp off of.

And you could then devolve into a war on the peninsula, which potentially could go nuclear.

(marching band playing) The way that I see North Korea is whatever decision is made, when they decide to test another nuclear weapon, test an ICBM, it's all in service of regime survival or perpetuation of Kim family rule.

They will not make a decision that will violate those.

And that gets back to the decision to assassinate Kim Jong-Nam.

Those decisions were taken because of the need for Kim Jong-Un to perpetuate his own power.

♪ ♪ >> NARRATOR: To this day, North Korea remains adamant that the man who was killed in Kuala Lumpur Airport was not Kim Jong-Nam but a citizen called Kim Chol, who died of natural causes.

Few are convinced.

>> It was like more sort of a dramatic and ingenious than James Bond film.

Of course, that was not completely successful.

They left behind so many traces of North Korean involvement.

>> 100% Kim Jong-Un gave the order.

There is no way, I would say zero possibility a North Korean agent can kill Kim Jong-Nam, the Supreme Leader's half brother, without direct guidance and order and approval by Kim Jong-Un himself.

>> The mission was a success in the fact that they killed Kim Jong-Nam.

None of the North Korean nationals implicated in this assassination has been brought for criminal charges.

People that say that this was a botched job are not thinking like North Korean intelligence operatives, they're not thinking like killers.

>> The operation by no means was perfect, but at the end end of the day, Kim Jong-Nam is dead, and Kim Jong-Un made a point that no one is safe.

The way in which Kim Jong-Un chose to kill Kim Jong-Nam, most brutal most ruthless, most painful way possible, I think this says a lot about the character and temperament of Kim Jong-Un himself.

>> The present leader eliminated one possible sources of a threat to his throne, but I do not believe that makes his throne more stable or secure.

One of the curses of-of the tyrant is that he or she never feels secure in the position of power.

>> Brutality, which is such a fundamental fact of an authoritarian regime, is a very tricky instrument to play.

(applause) Kim Jong-Un has tried to use brutality very publicly, very aggressively.

He's purged a huge number of senior officials, he has had them executed in very public ways.

And one of the questions is whether he's gone too far, and in so doing, has he begun the process of ultimately his own undoing.

Because that would become the ammunition that a challenge somewhere within the system would use to decide it may be time for another member of the Kim family to take over.

>> NARRATOR: Although Kim Jong-Un has removed the threat from his older brother, the Kim family tree still has many branches.

>> My name is Kim Han-Sol, from North Korea, part of the Kim family.

Here's my passport.

>> NARRATOR: Just three weeks after Kim Jong-Nam's death, this mysterious video was posted by a previously unknown group.

It shows Kim Han-Sol, Kim Jong-Nam's oldest son.

>> It shows that he's safe and it shows that he's alive.

You know, he could be a shadow darkening Kim Jong-Un's doorway at some point.

He could prove to be troublesome to North Korea down the line as a public figure, as a member of the Kim family, he-he could prove to be a nuisance to Kim Jong-Un.

>> (speaking Korean): >> NARRATOR: For now, North Korea continues to raise the nuclear stakes, claiming to have developed a hydrogen bomb.

>> (speaking Korean): >> If you study Kim Jong-Un it's impossible not to be impressed, to some degree, by his ability to fend off the critics, the threats, the people who said it was going to be impossible for him to do what he did.

This is a country that has a GDP that's one-third the level of Ethiopia, and yet he managed to generate enough precision, technical acuity, and money in order to build a nuclear missile program that poses a genuine threat to the United States.

By any measure that's an achievement.

It is also one, however, that has probably undermined the long-term stability of his own regime.

>> Rocket man is on a suicide mission for himself and for his regime.

>> From North Korea a unique threat vowing to make President Trump "pay dearly," calling him a mentally deranged dotard.

President Trump tweeted that the North Korean leadership won't be around much longer.

>> ...Very, very dangerous accusations, a top North Korean official now says President Trump has declared war on North Korea.

>> President Trump took to Twitter Sunday, appearing to cast doubt on the idea that diplomacy could resolve the crisis over North Korea's nuclear program.

>> ...the tension between North Korea and the U.S. is escalating.

>> ...and the risks of miscalculation rise.

>> At the end of the day, North Korea doesn't want to use these nuclear weapons, but they probably will if they believe the regime is at stake, that survival's at risk, and they have no other choice.

Kind of call that getting backed up into a corner.

If they're in the corner, they may well use it, they might know that the response would be overwhelming, but at that point it won't matter to them because they care most about the regime.

>> The E.P.A.

has an anti-fossil-fuel agenda.

>> Mr. Pruitt's fossil fuel dreams have come true.

>> NARRATOR: From fighting the E.P.A.... >> Lobbying is what makes the wheels of government turn.

>> NARRATOR: ...to running it.

>> It was eight years of pure hell under the Democrat Party and Obama, but we won!

>> NARRATOR: "Frontline" investigates.

>> What it amounts to is dismantling everything that previous administrations have done.

>> Go to pbs.org/frontline for more of our reporting on the tensions with North Korea.

Then listen to the latest episode of the Frontline Dispatch, a new original podcast series.

>> I'm Raney Aronson, "Frontline's" executive producer.

We're going to be tackling the toughest subjects.

>> I was caught in a car bomb in Mosul.

>> The thought of marriage at 14... >> They were killed by militiamen as they left... >> Subscribe now wherever you listen to podcasts, or at pbs.org/frontline.

>> For more on this and other "Frontline" programs, visit our website at pbs.org/frontline.

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