US president Donald Trump’s war of words with Kim Jong-un’s North Korean regime shows no sign of abating. The Western world is feverish with speculation on whether Trump is employing the Richard Nixon “madman theory,” where to buy a house outside a nuclear blast zone, and how the hell to survive if an attack does come.

What’s certain, though, is that old-fashioned diplomacy can shepherd the world out of this flare-up. We spoke to three experts who laid out how to do it.

Step One: Make contact

The two sides may not have official diplomatic relations, but there are at least two channels of communication open the US could use, says Joel S. Wit, who had senior roles in North Korea nuclear negotiations under president Bill Clinton. The first is the quiet dialogue they’ve been holding to secure things like the release of student Otto Warmbier: “It’s been sporadic, they’ve been trying to keep it extra low-key, and doing it in third countries where no reporters can find them—that’s the way they should do it,” says Wit, a senior fellow at Johns Hopkins and Columbia University.

If that fails, another channel is the North Korean mission to the UN in New York, but it’s not ideal, Wit says. “It’s a useful way of relaying messages but you’re not really going to accomplish a lot more than that.”

US secretary of State Rex Tillerson has openly offered talks to the North Koreans—but with the proviso that they freeze their missile launches before they even get to the table. That, however, “is not going to happen,” Wit says. To make that kind of concession Pyongyang will want something much larger than just a sit-down with the US. Instead, he argues, Washington should offer a preliminary meeting with no preconditions, something it’s so far refused to do.

Step Two: Lay out the demands

All the experts said the immediate deal will have to be some variation of a “freeze for freeze.”

Tom Collina, policy director at anti-nuclear foundation the Ploughshares Fund, explains what this might look like. “The United States and South Korea somehow reduce the military threat to the North, for example, by modifying the military exercises that are supposed to be starting later this month. In exchange for that, the North would agree to freeze its missile and nuclear program,” he says.

Beyond that, each side will lay out what it wants as the ideal endpoint of prolonged negotiations. The US will almost certainly say it wants a nuclear-free Korean peninsula. The North might push for a peace treaty with the US, the restoration of diplomatic relations, a permanent end to any US-South Korea military exercises, or some combination of the three.

Step Three: Slow, patient negotiations

If the North stops testing, that buys the rest of the world time to put pressure on the regime. For Pyongyang, meanwhile, reduced joint military activity between the South and the US would ease its sense of existential threat. Once that’s been agreed on, and everyone has calmed down a bit, formal negotiations can commence—with the aim being that the freezes kick in as official talks start.

Talks are slow and painful, moving closer together small offer by small offer, but they can work, says Wit, pointing to the (often derided) 1994 agreement he worked on as an example. At the time of the agreement, he says, the sense was that North Korea would have enough material to make 75 bombs within 10 years. The agreement fell apart in 2002 because the Koreans were discovered to have been cheating, but Wit says at that point they only had five bombs. The agreement had successfully stalled nuclear development by years, he argues.

Sounds great, but is it really that easy?

This is where the experts differ.

Wit says getting to the “freeze for freeze” point is “startlingly easy” and mainly being held back by trenchant views in Washington. For example, he says, the US can “easily” stop joint military exercises with South Korea, but argues there are many in Washington, DC policy circles who insist Pyongyang should reciprocate by stopping its own maneuvers. Wit argues there’s no point in pushing for that, since “we don’t care” about North Korean exercises, and doing so would ruin the most important quid pro quo: an end to US military exercises for an end to Korean missile tests.

Michael Mazarr, a nuclear weapons and East Asia expert at the RAND Corporation, is less bullish, arguing it’s going to be “devilishly hard…at this point it’s almost a coin flip” as to whether a freeze would work. He worries the Koreans may now feel so empowered by the strength of their nuclear arsenal as to realize that, if they keep developing it, the US may have to make more concessions, particularly as the threat of non-nuclearmilitary action seems to recede.

At the same time, a host of details will have to be nailed down if the two sides do start discussing a freeze. North Korea, for example, may want to stop all US-South Korea military exercises, while the US will only want to halt large ones. The US is also worried about the North Korean space program, which many consider a way of working on missile development without officially testing missiles.

Mazarr thinks the Koreans may also want to just draw out these negotiations as a stalling tactic. “They’re not going to agree to freeze until they’re at a level of nuclear development where they’re comfortable pausing, and I don’t think anyone knows precisely where that’s at,” he says. “They’re clearly racing to get to threshold.” As evidence, he points to the fact that the North has either turned down or ignored two offers of talks by South Korea in recent months.

Collina, on the other hand, simply doesn’t think Trump’s administration “has the wherewithal currently to pull [the negotiations] off.” “I have no sense that there’s any coordination or that there’s a plan at all other than Donald Trump doing whatever he wants,” he says. The other experts hoped—without any inside knowledge—that plans have been made behind the scenes while Trump blusters, with Mazarr saying he’s impressed by Tillerson’s “pragmatism and carefulness.”

Is there a plan B?

If the “freeze for freeze” doesn’t work, there are two options, Mazarr says. The first is that China comes to the rescue. “China has very fractured relations with North Korea right now, but they could easily try to jump in and create a trilateral dialogue between themselves and the two Koreas where they try to create a solution,” he says. However, he notes, Beijing doesn’t seem to have much appetite for that at the moment.

For the US, that leaves just one option: ramping up the kind of containment policy used on the Soviet Union and developed by legendary US diplomat George Kennan in the 1946 “Long Telegram” (pdf). That means a number of steps, Mazarr says:

  1. Invest in a “powerful deterrent and convey to the North Koreans that any form of aggression will be met with devastating consequences.”
  2. Ease Pyongyang’s paranoia by conveying that “we don’t intend to be a threat if they don’t undertake aggression.”
  3. When they do make small provocations, like the alleged sinking of a South Korean ship in 2010 (which Pyongyang denies doing), respond “very quickly in a moderate and proportional way” so they know not to mess around.
  4. “Play for the long game.” That means undermining the regime by smuggling in information that subverts it, trying to increase contacts with South Korea, giving North Koreans cell phones—all while squeezing the government with sanctions.
  5. Eventually, hope North Korea will come to the table and start working on the kind of arms reduction agreements developed with the Soviet Union.

Would this succeed? Mazarr believes so. The main risk, he says, is that the North may get carried away and try to annex the South. But he doesn’t think the country will risk nuclear war over that: “I see very little evidence that they are irrational—they mainly want a continuation of the regime.”

Lola Fadulu contributed to this report.