It’s astonishing how quickly the story of the North Korea crisis seems to have changed from one of fear to one of optimism. It was less than a year ago that the U.S. president was threatening “fire and fury” against Kim Jong Un, the leader of North Korea, to touting upcoming talks with him. It is not the case, as Trump tweeted Sunday morning, that the North “agreed to denuclearization.” But the North’s recent declarations that it would at least talk about denuclearization, and put a moratorium on the nuclear and missile tests that kept the world on edge last year, certainly do look like significant concessions.Or do they? Does this all really mean that the North Korean nuclear issue, the scourge of U.S. policy makers for decades, is about to be solved? Not at all, even if recent developments provide some grounds for—very conditional—optimism.Only a year ago, the Kim regime had reasons to be happy. In 2017, it tested two long-range missile prototypes capable of hitting the continental United States with a nuclear warhead, and also exploded its first hydrogen bomb. But Kim soon found himself contending with a rather unconventional U.S. president in Donald Trump, who promised to use armed force if the North Koreans did not agree to abandon their nuclear program. This was new. For decades, North Korea has been certain that the United States would never strike first: Seoul, the capital of South Korea, the closest U.S. ally in the region, lies within range of North Korean heavy artillery. If the North retaliated, hundreds of guns would transform downtown Seoul into an inferno. Such a crisis would be followed by a war of immense destruction.But Trump has altered this calculus. While his “fire and fury” threat may have been a bluff, he has persuaded the Kim regime that it is dealing with a president who is willing to risk Seoul (along with the U.S.-South Korea alliance). A U.S. military strike, Kim has come to see, is no longer an impossibility. Trump’s threats also persuaded China to support the toughest sanctions regime ever imposed on North Korea, making it near-impossible for it to sell anything on the international market. So far, North Korea’s increasingly market-driven economy is doing surprisingly well. But that won’t last forever—something the Kim regime knows. North Korea, as a result, chose to retreat. In November 2017, it halted its nuclear and missile tests, and on Saturday, reiterated this position in dramatic terms.While all this sounds great, it doesn’t alter one simple truth: North Korea will never fully surrender its nuclear weapons. From Kim’s point of view, nuclear weapons constitute his only guarantee of survival. North Korea saw what happened to Saddam Hussein, whose attempts to develop nuclear weapons were cut short by an Israeli air-force raid in 1981. It saw how things went in 1994, when Ukraine surrendered its Soviet-era nuclear heritage in exchange for “guarantees” from the United States, Britain, and Russia, to respect its territorial integrity. Above all, North Korea remembers the sorry fate of Muammar al-Qaddafi of Libya, the only dictator in history who agreed to surrender his half-baked nuclear program in exchange for economic benefits. This is why the Kim regime has spent 60-odd years building up its nuclear program.Nonetheless, North Korea now needs to neutralize what looks like the looming threat of a U.S. military strike, while also relieving the pressure of sanctions. Thus, the North Koreans have to make concessions. They will indeed stop testing, and they might agree to surrender some of their equipment and weapons, and profess a theoretical commitment to eventual denuclearization. (Such lip service won’t mean much: According to the 1968 Non-Proliferation Treaty, the United States, as well as virtually every other nuclear power, is also formally committed to eventual denuclearization.) However, the North Koreans will insist that denuclearization should happen gradually and in stages—they have already said so, and found a hint of Chinese support. Then, they will ensure that these stages will be numerous and prolonged, thus winning time in hopes that sooner or later the White House will have a more conventional inhabitant.But it would be a big mistake for Trump and his advisers, some of whom will see through the scheme, to refuse to compromise and demand an immediate and full capitulation. Surrender is not going to happen: If confronted with the choice between denuclearization and dealing with famine and bombing, North Korea’s leaders will choose the latter. An imperfect compromise is better than a large-scale war—not another Afghanistan or Iraq, but another Vietnam.One hopes, then, that President Trump accepts a compromise deal—perhaps one in which he offers to reduce the U.S. naval presence in the region, or some economic relief. He should squeeze as much as possible from the North Koreans—judging by their behavior in recent months, they are ready to give up a lot—and then go home.