A version of this article appeared in China Newsweek (Chinese). Questions from Li Jing of China Newsweek in conversation with Siegfried Hecker (Interview from October 2018).

Recently, the leaders of the two Koreas met again, and they signed a joint declaration which they said would bring peace to the Peninsula. How do you like the meeting and the declaration? Do you think it helpful to the denuclearizing? If so, how will it help?

The meeting was very positive. It helped to bring the two Koreas closer together and moved them in the direction of bringing peace to the Peninsula. The declaration was also positive, but somewhat vague. It offered the promise of denuclearization, but the difficult work remains to be done. The agreement on military cooperation is a big step in helping to reduce tensions between the two Koreas.

According to your assessment, what kind of nuclear capability does the North Korea have? Is it a de facto nuclear power?

There are many uncertainties about North Korea’s nuclear capabilities. However, based on what we know about its nuclear complex and the six nuclear tests it conducted, North Korea may have sufficient nuclear material, that is, plutonium and highly enriched uranium, for approximately 20 to 60 nuclear weapons, with 30 being the most likely number.

North Korea has a wide array of missile capabilities. It is quite likely that North Korea has miniaturized nuclear warheads to fit on the short-range SCUD missiles and medium-range Nodong missiles and therefore may be able to reach all of South Korea and most of Japan. North Korea has demonstrated that it can launch ICBM’s (Intercontinental Ballistic Missiles), but it has done so only on high flight trajectories rather than normal trajectories. That means it must do more missile tests before it has a reliable ICBM. It has also not demonstrated that it can make a nuclear warhead sufficiently small, light, and robust to survive an ICBM flight.

I do not consider North Korea to be a nuclear weapon state, but it is a state with nuclear weapons, which does make it a de facto nuclear power.

Do you think the North Korea positive measures, including dismantling the Punggye-ri site, bears any substantial significance in terms of denuclearization? Were these measures reversible?

Stopping nuclear testing and ICBM testing were important positive steps. Closing the Punggye-ri nuclear testing tunnels was also an important step. Yes, these can be reversed, but a resumption of nuclear testing will now require much time and will be easily visible.

Since this year, the situation of the Peninsula issue has been improving very fast. Did you feel surprised by such a turn of the Peninsula situation?

The Year 2017 was very dangerous because of the technical advances that North Korea made with its nuclear programs, namely the big nuclear test in September and the ICBM missile tests. In addition, the political rhetoric was extremely dangerous. However, many positive things happened in 2018. The most important is that politically, we stepped away from the precipice of war, and that is good news, and somewhat unexpected.

It is reported that a second summit between the US and the DPRK may take place. If it is true, what fruit do you think the summit can yield? Do you think the first summit between President Trump and Kim Jung-un has opened the door to the denuclearization?

Yes, the Singapore Summit definitely opened the door to a resolution of the North Korean nuclear crisis and the possibility of the denuclearization of the Peninsula. The summit was made possible by President Moon Jae-in and Chairman Kim Jong-un taking important steps toward reconciliation. And, President Trump welcomed the opening and met with Chairman Kim. The Singapore declaration was very basic focusing on the overall objective of normalization and denuclearization. It left the difficult work for the future. A second summit should now agree on specific steps toward denuclearization and normalization.

The US insists on no relief of sanctions before complete denuclearization, but the DPRK seems expecting a step-to-step model. The positions of the two sides are very far apart. Do you think the two sides can find some space to make compromise in order to press ahead with the denuclearization?

I believe a step-by-step approach will be necessary, but on the North Korean side the steps will have to significantly reduce the risks its nuclear program poses. On the American side, the steps will have to make progress on normalization. These kind of steps for each side should be on the agenda for the second summit.

It has been reported that after the Singapore summit, the US has asked the DPRK to provide a list of its nuclear capabilities, which was rejected and regarded as confrontational by the DPRK. How much knowledge do the outside world have about the DPRK nuclear capability? Will a list mean a total surrender to the US?

From my perspective, what is more important is to first take concrete steps to reduce the nuclear risks. Two such steps, namely, no nuclear testing and no ICBM missile tests have already been taken by the DPRK. Next in importance is to stop plutonium production. That means to dismantle the 5 MW-electric reactor in Yongbyon and not start the Experimental Light Water Reactor under construction.

It may be appropriate to ask North Korea for a list of the Yongbyon facilities early in the negotiation process, but I believe a full declaration is not yet possible. The level of trust required for such a declaration does not yet exist. Eventually, North Korea will, of course, have to provide full declaration and agree to a strict verification regime.

Do you think the six party talks will still be significant after the DPRK and the US are holding bilateral talks?

It is not clear to me whether or not the six-party talks will be useful. However, it is very important that the other parties, namely, China, Russia and Japan, each play a supportive role in the denuclearization and normalization process. Those roles and that of the UN Security Council are yet to be defined.

You have predicted in a report that the DPRK will not abandon its nuclear capability at least in the coming 15 years. What are the major hindrances to a complete denuclearization of the DPRK? Is there any possibility for the related parties to persuade and press the country to start the denuclearization in the near future?

My Stanford University colleagues, Robert Carlin and Elliot Serbin, and I have published a comprehensive history of the North Korean nuclear program. Based on that history we developed a 10-year roadmap for denuclearization, rather than the 15 years quoted in the news media. Actually, it is better to call this a “framework,” because the real roadmap will have to be determined through negotiations.

It recommends three phases toward denuclearization. The first is to “halt” – that is, don’t make it worse. Second, take specific steps to “roll back”, reduce the threat - so no nuclear testing, no missile testing, no more plutonium. The uranium facilities will also have to be addressed, but that will take more time because only the Yongbyon centrifuge facility is known. North Korea has more centrifuge facilities that will eventually have to be addressed. The third phase is to “eliminate” all weapons and facilities that support the nuclear weapon program. Those facilities that would support only a civilian program will have to be addressed during negotiations. Our framework indicated that the first phase could take up to one year, the second would take possibly four more, and the third would be completed by the tenth year.

This process could be accelerated if sufficient trust can be developed between the DPRK and the United States. One possible way to build trust and speed up the process is to have the US and South Korea tell Chairman Kim that they are willing to help him convert his military nuclear and missile programs to civilian nuclear and space programs. Having American and South Korean technical specialists working side-by-side with DPRK specialists at their nuclear and space facilities would provide the best approach to verification of denuclearization.

And, let me also say, there is a potential role here for China as well as for Russia. China can help the DPRK with nuclear reactors for electricity and Russia could provide launch services for DPRK satellites.

Based on the current advancement of the DPRK’s denuclearization and the possibility of a fruitful second Trump-Kim summit, do you think the DPRK’s process of denuclearization goes in a way as reflected by the three-phase approach in the ten-year roadmap put forward by you? Which one of the three phases is the most important and which one is the most difficult?

So far, North Korea has begun the first phase of our ten-year roadmap, namely to begin to halt nuclear development. Pyongyang has stopped nuclear testing and stopped long-range missile testing and has promised to dismantle facilities at the Dongchang-ri Satellite Launching Station. The next important step is to stop reactor operations so as not to produce more plutonium. The Trump administration is pressing for a declaration of North Korea’s nuclear inventory as the next step in the process. While a declaration at some point would be consistent with the three-phrase approach, right now it would not be as valuable as halting operations at Yongbyon and may in fact be counterproductive. I hope that the next Trump-Kim summit will start the second phase, that is to seriously roll back the nuclear and missile programs. The most difficult step will be the last one – that is, to eliminate all military nuclear and missile programs. That will require the development of trust between the two parties and help from the other parties such as South Korea, China and Russia.

When the DPRK allegedly dismantled the Punggye Ri nuclear test site, there was no international technical personnel present on the spot to witness. Based only on media reports, do you think it is possible to confirm the site has been substantially dismantled?

During the 7 October Kim-Pompeo meeting, Chairman Kim apparently agreed to allow international inspectors to the test site. This is a very important step to build confidence that North Korea is taking serious actions to halt their nuclear program. The inspectors should be able to assess how complete the destruction of the tunnels is and what would be required to re-activate them. For North Korea to give up nuclear testing is one of the most important steps in denuclearization.

How does the international community effectively monitor the denuclearization measures such as suspension of nuclear tests and launch of missiles, suspension of uranium enrichment? Are these measures reversible? If they resume such activities, will it take a long time and be visible to the outside world?

Monitoring an end to nuclear testing and long-range missile launches is easy. It can be done with great confidence. Monitoring the operation of the plutonium-producing reactors is also very effective using commercial satellite imagery. There is no way to monitor uranium enrichment facility operation without cooperation from North Korea. Of course, most operations are reversible. However, resuming nuclear testing will be difficult if the tunnels are effectively destroyed. To make plutonium production irreversible, the reactors would have to be incapacitated (poisoned or destroyed). There is not much that can be done to confirm the suspension or prevent the resumption of uranium enrichment because no one outside of North Korea knows where all the facilities are.

How should the US compensate for the DPRK’s real denuclearization? What incentives can the international community provide to the DPRK in terms of creating a more beneficial environment?

I would not look at this as compensation – we should not be viewed as paying off the North Koreans to give up their nuclear weapon program. Besides, I believe that what they want most is security guarantees. For this, one has to ask the North Koreans what they require. Since Chairman Kim appears very serious about improving North Korea’s economy, I believe he will ask for relief of sanctions so they can develop their economy. The US should be prepared to match North Korea’s denuclearization actions with steps toward political normalization and sanctions relief.

Based on the interactions of different parties this year, especially the negotiations between the US and the DPRK, how probably do you think the DPRK leader Kim Jung-un will be committed to a complete denuclearization? Compared with his father, is he more confident and more steadfast in embarking on the road of focusing on economic development?

The history of negotiations is long and complicated. No one outside of North Korea really knows what Kim Jung-un is prepared to do. However, he has taken important and encouraging steps toward denuclearization and expressed his deep commitment to economic development. Since the actions taken by Kim Jung-un, President Moon Jae-in and President Trump in 2018 have moved us away from the brink of war, I think it is time to test just how far Chairman Kim is willing to go toward denuclearization and normalization. Time will tell.