Kim’s current unwillingness to stop fissile material production is highly significant for two reasons. First, it allows the North Korean leader to credibly claim the North’s nuclear deterrent is expanding and he has not caved in to US pressure even though the moratorium on nuclear and missile tests remains intact.

But it also raises a deeper, more troubling, question: if Kim is unwilling to take the preliminary step of ending fissile material production, how can he be expected to carry through on denuclearisation? In short, it is hard to envisage further progress on denuclearisation unless and until there is agreement on terminating the production of fissile material at all sites, that is, ending the reprocessing of plutonium and deactivating centrifuges at Yongbyon and other undisclosed sites.

If Hanoi served a purpose, it was to demonstrate where the political fault lines lie and that nibbling around the edges is unlikely to result in an agreement acceptable to both sides. In sum, it is doubtful that Washington can convince Pyongyang of its peaceful intentions or that Pyongyang can give up enough of its nuclear programme to convince Washington of its sincere desire to denuclearise.

More fundamentally, the Korean peninsula has been locked into a “division system” since the Korean war nearly 70 years ago, with the US and South Korea arrayed against China and North Korea. Although the two Koreas have begun to forge a new non-hostile relationship based on the Panmunjom peace declaration of April 2018, Washington and Pyongyang have yet to explore alternative security arrangements, including multilateral security guarantees.

The key question now is whether diplomacy can fill the void. Outside powers, like the US and China, in particular, have an important role to play. Thus, in a speech to the UN Security Council in September 2018, Chinese Foreign Minister Wang Yi stressed: “China believes that the best way forward is to pursue denuclearisation and the establishment of a peace regime in tandem through a dual-track approach, whereby the two objectives would be mutually reinforcing and will be achieved at the same time.”

As the North’s major trading partner, with the lion’s share of North Korean exports and imports flowing through Chinese ports, China has considerable political leverage in terms of potential sanctions relief. While Chinese-North Korean trade is currently impeded by sanctions, modest sanctions relief in exchange for an end to fissile material production would be a good first step in getting the process back on track.

Finally, Sino-American cooperation is necessary for progress towards denuclearisation and a stable and lasting peace regime. As former US secretary of state Henry Kissinger wrote in The Wall Street Journal in August 2017, “An understanding between Washington and Beijing is the essential prerequisite for the denuclearisation of Korea. … A joint statement of objectives and implicit actions would bring home to Pyongyang its isolation and provide a basis for the international guarantee essential to safeguard its outcome.”

On that basis, the US and China should give joint security guarantees to the two Koreas, superseding the current US-South Korean security alliance.

John Barry Kotch is a political historian and former State Department consultant