There’s a line in Taoist philosophy that says, ‘The Tao that can be spoken is not the eternal Tao.’ It’s a cautionary principle that should underpin one’s reading of the final joint declaration from the Trump–Kim summit in Singapore.

The declaration itself is short on detail, and commits its signatories only to four grand objectives: a new bilateral relationship between the US and North Korea, a peace regime on the Korean peninsula, complete denuclearisation of the peninsula, and recovery and repatriation of the remains of prisoners of war or soldiers missing in action from the Korean War. When it was released, the Twitterverse exploded with indignation and outrage, generally along the lines of, ‘Is that all?’

But I’d put a more positive spin on the summit—largely on the basis of what the joint declaration doesn’t say. A close reading of the tea leaves suggests there’s more happening here than meets the public eye. Indeed, the fine detail of denuclearisation is being kept well off camera.

The two sides seem to have agreed not to talk about that issue much—not least, I suspect, because Washington believes that doing so would only make it harder for Kim Jong‑un to make the concessions necessary to make denuclearisation a practical policy option.

Readers should go back and look again at the ‘Libyan model’ of nuclear disarmament. True, public discussion of this model became entangled with a separate event, namely Muammar al‑Qaddafi’s unseemly end. But take a closer look at the events of 2003 and 2004. Libya cooperated closely in dismantling its own WMD programs. There was a high level of transparency in that process, but only for a small group of people—it wasn’t a public process. US and British foreign and intelligence officials and International Atomic Energy Agency inspectors had the best view of what was happening on the ground. John Bolton was, at that time, Under Secretary of State for Arms Control and International Security.

Keeping the denuclearisation issue off camera in relation to North Korea clearly involves some verbal gymnastics in US descriptions of what took place at the summit. In his hour-long press conference with media, President Donald Trump spoke of a sudden, belated, incidental agreement between the two leaders to dismantle a ballistic-missile engine test site in North Korea, suggesting that this concession had come too late to be included in the text of the joint declaration. (‘We agreed to that after the agreement was signed.’)

That’s possible, I suppose. But it would seem to fit more logically in a discussion over whether the moratorium on ballistic missile testing also included static missile engine tests—of which the North Koreans do quite a few. And that would imply both sides have begun to burrow down on matters of detail.

Trump uses the idea of the belated agreement on engine testing to suggest to journalists that not everything that was agreed appears in the declaration. ‘[W]hat we signed today was a lot of things included (sic). And then you have things that weren’t included that we got after the deal was signed.’

At later point in his press conference, Trump is asked again about the lack of detail on verifiable and irreversible denuclearisation. He replies that ‘it wasn’t a big point today because, really, this had already been taken care of, more than any other thing … This has been taken care of before we got here.’ So some points never made the declaration because they came too early.

Asked about whether American or international inspectors will actually be present on the ground to verify North Korean denuclearisation, Trump states that ‘combinations of both’ will be involved. ‘And we have talked about it, yes.’

In an interview with George Stephanopoulos on ABC News, the president stated that ‘we have the framework of getting ready to denuclearise North Korea’. Here, he talks about denuclearisation in more sweeping terms, and the message is definitely about a process that is imminent and not distant.

So, how should we judge the Singapore summit? Well, it was definitely a public relations win for both leaders—which probably plays out to Kim’s relative advantage. Moreover, Trump’s announcement about the cessation of US–South Korean military exercises clearly caught the South Koreans flat-footed, so an awkward moment for Washington there. But on the biggest point of all, denuclearisation, the honest answer is that it’s too soon to tell. More seems to be happening than meets the eye.

Despite evidence of belated second thoughts by the principal players (see here and here), a summit meeting between President Donald Trump and Kim Jong‑un is still likely to occur in Singapore on 12 June. In a recent column for the New York Times, David Sanger outlined the US administration’s super-sized expectations: that Kim will agree on denuclearisation, and accept a schedule that would see ‘some number of nuclear weapons’ handed over during the following six months, while American inspectors would enjoy virtually unlimited access to oversee the closure and dismantlement of key North Korean production facilities.

But Pyongyang’s hostile reaction last week to talk of the ‘Libyan model’ suggests that if Kim Jong‑un believes in North Korean denuclearisation at all, it’s only on the never-never plan. He might well entertain his own inflated expectations. North Korea has long fancied a version of the US–India nuclear deal for itself: one that recognises and accepts North Korea as a legitimate nuclear state; enmeshes the country in broader patterns of economic growth; and dilutes the security threat posed to the North by the presence of US forces in Northeast Asia.

So what should we expect the summit to deliver? Some things are relatively clear: a summit that produces merely a statement of principles won’t cut the mustard. Been there, done that—see the joint declaration of principles agreed during the Six‑Party Talks in September 2005. Writing it out again would be a waste of time, paper and ink.

Similarly, an outcome that pushes all the big decisions down the track, and depends upon the long-winded meetings of factotums, would also be seen as a failure—not least because Trump has cast both himself and Kim as history makers, not as meeting convenors. True, the natural order of things has been inverted here, because successful summits usually follow—and are the products of—the heavy lifting of numberless sherpas.

Obviously in this case a successful summit would need to set in train a program of engagement and activity, but Trump and Kim would probably both want to be associated with a grander outcome than a call for sherpas to gather.

So, not just a statement of principles, and not just a program of future meetings. Nor can it be a summit that merely rubberstamps actions already undertaken, such as the closure of the North Korean nuclear test site at Punggye-ri. Closing the site is a useful indicator of intent, but reversible.

Some evidence suggests the North Koreans might be prepared to sign and ratify the Comprehensive Nuclear Test Ban Treaty, but I suspect they’d want a joint commitment from Washington to do the same—and that proposal would probably die in the US Senate.

Then, of course, there are the tests that most commentators will apply to determine whether or not Kim is serious about restraining his nuclear program. For Washington, an outcome that doesn’t bear down on the threat to the US homeland (from North Korea’s Hwasong‑14 and Hwasong‑15 ICBMs) won’t be acceptable. North Korea might not, in the first instance, have to surrender the missiles themselves—but probably would have to surrender (in that elliptical phraseology) ‘some number’ of guidance systems.

Thermonuclear warheads might well fall in the same category. Complete, verifiable and irreversible denuclearisation is clearly a bridge too far for Pyongyang, but the Americans will want—initially—to ‘corral’ the North Korean program to the level of threat it posed in 2016, when it had a limited-yield fission warhead and no proven long-range ballistic missile capabilities.

Washington has also got to be looking for a way of ‘turning off the tap’: stopping the production of fissile materials (plutonium and highly enriched uranium) and the manufacture of a range of different ballistic missiles. It may take some time to determine Pyongyang’s existing fissile material and missile inventories, but a key priority will be to halt further growth in those inventories. Stopping plutonium production would be especially valuable because plutonium is a more energetic material than enriched uranium.

On the missile side, the Americans are probably hoping to see a near-term dismantlement of the ICBM factory. Further down the track, they’re probably keen to see North Korea return to far more limited ballistic-missile capabilities—though I’m wary of using the phrase ‘the Libyan model’, that model’s endorsement of Missile Technology Control Regime thresholds as an acceptable missile constraint might also apply here.

That’s a huge agenda. How much of it will actually form part of a summit outcome? Probably less than we’d hope. And even if all of it is on offer, it might well be at a price—US withdrawal from the peninsula?—that not all in Washington would be willing to pay (though Trump himself might be).

Still, just as Goldilocks eventually found a bowl of porridge that was neither too hot nor too cold, we should anticipate a ‘deal’ in Singapore—one that erases some of North Korea’s recent gains in exchange for various rewards. Much less likely is the prospect of a ‘grand bargain’ that shapes the future strategic environment in Northeast Asia. Neither side seems quite ready for that.

Of course, it’s not quite as simple as finding a ‘win‑win’ solution for Trump and Kim. Any deal is likely to touch on the interests of all parties to the Six-Party Talks—so we can expect all of them to be leaning on Washington and Pyongyang to find a ‘win-win-win-win-win-win’ solution. That’s a burden neither Trump nor Kim will be keen to embrace.

For nearly 70 years, nothing has interrupted North Korea’s fierce and often savage belligerence towards the South and its superpower ally, the United States. Now President Donald Trump has spontaneously accepted an invitation to meet his North Korean counterpart, probably in May, and probably on the 38th parallel that separates the two Koreas.

Trump was reportedly so excited that he was prepared to let the South Korean official who had delivered the invitation make the public announcement from the White House—until the protocol police intervened. Late last year, the president was prepared to humiliate his secretary of state by tweeting that floating the possibility of unconditional discussions about denuclearisation (as Rex Tillerson had done) was a ‘waste of time’.

The invitation from Kim Jong-un was indisputably juicy: he explicitly declared that North Korea’s denuclearisation would be on the table; he promised that there would be no North Korean nuclear or missile tests in the lead-up to or during the summit; and he volunteered that he ‘understood’ that the US and South Korea would not suspend their regular military exercises. Kim really wanted a ‘yes’.

Much of the administration, not to mention the wider ‘swamp’ in Washington DC, was aghast. That alone may well explain a larger part of President Trump’s motivation than anyone dares to openly acknowledge—and represents a skilful piece of long-distance character assessment on the part of Pyongyang.

Even China, North Korea’s de facto father and formal ally—which has for decades hovered serenely around the edges of this ugly issue urging a peaceful solution—was distressed at the prospect of being excluded from a primary channel of communication, as well as from a North–South summit being planned for the lead-up to the Trump–Kim event. China promptly offered to host the major summit in Beijing, seemingly without receiving a response.

Some older hands have chosen to stress that there are good reasons why international summit meetings are mostly held in reserve during difficult and consequential negotiations. They’re a special diplomatic tool that can serve as an incentive to complete an agreement, or be deployed when agreement is close but can’t quite be reached on a couple of core issues.

These analysts point out that North Korean denuclearisation is a complex, multi-faceted undertaking that, even in the best of circumstances, will take many years to accomplish. The two sides have twice taken a pretty serious look at what would be involved: in 1993–1994 and in 2005–2006.

The contention that a single summit could deliver the sort of broad and in-depth agreement needed to sustain the follow-on negotiations is considered a pipe dream. One might imagine a leaders’ agreement to meet again as and when the negotiations require, plus a hotline to cope with lesser stumbling blocks. But many still consider that a needlessly high-risk approach.

Probably the bigger question is why Kim Jung-un was prepared to say that he’s willing to give up his nuclear weapon and long-range ballistic missile program, a capability that he has positioned as utterly central to North Korea’s long-term future and something that has cost North Korea dearly in successively harsher sanctions regimes.

A cynical response has been that Kim will simply capitalise on Trump’s ‘engagement’ with him, including when Kim’s conditions force Trump to be the one to declare ‘no deal’.

But might there be another motive in play—that Kim has been manoeuvring to maximise his negotiating leverage and judges that he’s now in the strongest position to get a good deal for North Korea’s long-term future?

We know quite a bit about what North Korea values: a peace treaty to replace the 1953 armistice; security assurances, probably from all three major powers—the US, China and Russia; regional recognition and acceptance, including through diplomatic relationships; long-term economic and technological assistance, probably including nuclear power plants; and taking appropriate care at all times to portray the DPRK as fully comparable to South Korea.

There are several factors that converge to suggest that this is North Korea’s game. First, North Korea has yet to close an important technological gap—the ability to develop a reliable re-entry vehicle to take its nuclear warheads from space, through the heat and turbulence of the atmosphere, and over their targets before detonating. Demonstrating mastery of this last piece of the technological puzzle could be fraught with risk, just the sort of shock that might compel a US president to authorise a surgical strike on key components of the North’s nuclear infrastructure. Whether Trump is seen as a particularly dangerous president from this standpoint is an open question.

Second, it’s thought that the most recent sanctions have hit particularly hard, offering North Korea a realistic picture of an indefinite future of limited options and close dependence on China.

Third, there are several China-related considerations that can be added to this mix. China has often taken declaratory positions against Pyongyang’s nuclear program but shied away from any actions that might actually impede that program. That has begun to change, with China implementing some of the harsher recent sanctions.

In a related shift in late 2017, China appears to have responded to US overtures to discuss how American and Chinese forces could avoid running into one another if military action were taken against North Korea’s nuclear capabilities. China had resisted engaging in such discussions for a number of years.

These straws in the wind could suggest that Beijing has concluded that its long-standing posture of disguised tolerance of the North’s progress toward a nuclear capability has been a mistake.

Finally, if Kim is indeed truly interested in cutting a deal, his bold proposal offers the possibility that the channel to the US will be the pre-eminent one in the ensuing negotiations and help to diminish China’s ability—because of history, proximity and sheer strategic weight—to dominate the outcome.

There’s enough here to suggest an intriguing possibility, but it’s still very hard to see it as a probability.

As North Korea’s nuclear and ballistic missile programs have become more adventurous, a worrying possibility has begun to emerge. There’s a chance that—at some point—the North Koreans might want to combine the two testing programs, by putting a live nuclear warhead on top of a ballistic missile. That means, assuming all goes as it should, the missile would fly downrange to its appointed target zone, and the warhead would detonate in the atmosphere. That sort of test—an end-to-end test of the full weapon system—would be a convincing demonstration that Pyongyang had crossed the critical bridges: that it had a long-range ballistic missile with the throw-weight to carry a nuclear warhead, a warhead able to be placed atop the missile, and a re-entry vehicle that could survive the stresses of re-entry.

It would also be dangerous. A lot can go wrong during a ballistic missile test. When things do go wrong, missile controllers usually order the missile to self-destruct. But most missile tests don’t involve live nuclear warheads. Besides, in the early stages of a missile’s development, testing is primarily about learning the limitations and vulnerabilities of the particular weapon system. Becoming familiar with a ballistic missile typically involves a number of launches—and God knows North Korea does few enough of those as it is. Remember the Hwasong-12, Pyongyang’s intermediate-range ballistic missile? It’s been tested six times. The Hwasong-14 ICBM? That was tested twice, both times on lofted trajectories. The latest missile, the Hwasong-15, has been test-fired only once—again, on a lofted trajectory.

Well, you might think, surely they have older, better-tested missiles somewhere in their arsenal. Sure they do, but those are generally short- and medium-range missiles—which aren’t of much use if the point is to lob a warhead somewhere out into the distant reaches of the Pacific Ocean. Putting a live nuclear warhead on a missile that wouldn’t clear Japan isn’t an option. But putting one on an under-proven longer-range delivery vehicle doesn’t sound like a smart move either. Still, Pyongyang might be tempted down that path in order to demonstrate the ‘completion’ of its programs.

Such tests have been done before by other nuclear-weapon states. True, they’re incredibly rare, and no such test has been conducted since the 1960s. In 1962, the US conducted a nuclear test involving an operational submarine-launched ballistic missile. The test, code-named ‘Frigate Bird’, was held on 6 May. It was ‘the only US test of an operational ballistic missile with a live warhead’. It involved the launch of a Polaris A1 SLBM from the submarine USS Ethan Allen, a missile flight of about 1,000 nautical miles, and the atmospheric detonation of a 600-kiloton nuclear warhead in the vicinity of Christmas Island. (Let me hasten to assure Australian readers that the ‘Christmas Island’ in question was in the Line Islands in Kiribati, and not off the northwest coast of Australia.)

Although the details are sketchy, the Russians seem to have done something similar in Test 95, conducted on 13 September 1961. An SLBM launched from the Barents Sea flew to the test range on Novaya Zemlya. As a safety measure, the Russians seem to have deliberately replaced the missile’s usual warhead with one of reduced yield, since the resulting nuclear detonation was about 6 kilotons. Some sources suggest there might have been other such tests as well, though it’s important to count only those that actually involved ballistic missiles, rather than other weapon systems.

In October 1966, the Chinese conducted a nuclear test involving the ballistic-missile delivery of the warhead to their Lop Nur test site. This test was CHIC-4, held on 27 October. The missile was a CSS-1 medium-range missile, which flew about 900 kilometres before the warhead—a simple fission design with a yield of approximately 12 kilotons—was detonated in the atmosphere. CHIC-3 had a yield of 250 kilotons, and CHIC-5 300 kilotons, so it’s reasonable to conclude that the Chinese also made an effort to dial back the CHIC-4 yield as a safety precaution. (As a point of interest, the CHIC-4 design—labelled ‘early, [and] inefficient’ by the CIA—is the one the Chinese later shared with the Pakistanis.)

Given that the US and Russia have both conducted end-to-end tests by using SLBMs, Kim Jong-un might be drawn to pursue a similar option. An SLBM needn’t involve overflight of Japan. And it would allow the test to be conducted remote from major urban areas. But that assumes, of course, that Kim has a working SLBM, not to mention a submarine capable of launching it—which he probably doesn’t at this point in time. What Kim has is an under-tested ICBM capability, plus of course an under-tested intermediate-range ballistic missile capability. If he decides to try for an end-to-end nuclear test with one of those, we might be in trouble.

None of the previous tests by the US, Russia and China, remember, have involved an intercontinental-range or even an intermediate-range missile. Any scenario in which Pyongyang attempts such a test—humorously labelled ‘Juche Bird’ by some—is fraught with danger. Indeed, even the preparations for such a test, including the loading of a nuclear warhead onto a long-range missile, might well trigger a US pre-emptive strike. After all, how could a US president be confident that a nuclear-tipped ICBM was being launched only for testing purposes?

Note: An earlier version of this post said that the Hwasong-12 had been tested three times; the figure has been corrected to six (three successes and three failures).