U.S. relations with South Korea couldn’t be better. Alas, relations with North Korea could hardly be worse. The Biden administration is celebrating the former with a state visit by South Korean President Yoon Suk-yeol. In contrast, the administration has nothing to say to North Korean leader Kim Jong Un, who refuses to engage with the United States.

As a result, even a triumphant summit with Yoon is, at best, a hollow victory for Washington. U.S. relations with the South are not in doubt. Although Washington and Seoul sometimes disagree on strategy toward the North, even left-leaning South Korean presidents, such as the redoubtable Kim Dae-jung, have been committed to the alliance. In contrast, North Korea is increasingly acquiring the means to challenge the U.S. security commitment to the South.

At the inconclusive end of the war 70 years ago, the Eisenhower administration agreed to a mutual defense treaty with South Korea. The latter probably would not have survived without the U.S. guarantee, backed by a military garrison. The promise was relatively simple to make. The danger of renewed fighting was real, but the danger to the United States was limited, since North Korea had no means to harm the U.S. homeland. The American people were taking a risk but one that was bounded.

Over the last decade, the threat environment has changed dramatically. Pyongyang developed nuclear weapons and a multitude of short- and medium-range missiles, increasing the danger to South Korea and Japan as well as U.S. forces stationed elsewhere in the region, including in Guam. Even then, the U.S. mainland remained well beyond the North’s reach. Successive administrations relied on deterrence, since the Kims were united in staying alive. However, North Korea was also acquiring a deterrent.

Today, the latter looms especially large. The North has been moving ahead in a number of areas. Last year, it launched nearly 100 missiles. The tally is more than 20 so far this year. And a nuclear test is still expected. Although the North’s capabilities and intentions remain uncertain, both rhetoric and behavior suggest that Kim Jong Un is intent on developing a significant nuclear arsenal with the missiles necessary to target U.S. cities. The lethality of his strategic strike force would be enhanced by MIRVs, or multiple independently targetable reentry vehicles, with each missile carrying several warheads, and submarine-launched missiles.

Even if he succeeds in these efforts, Kim could not attempt a first strike. That would result in almost instant annihilation of his state and dynasty. However, if his rule were endangered, it’s likely that within a few years he could threaten to retaliate against U.S. cities. All he would need is the reasonable likelihood that a few missiles with a few warheads each would get through, and the U.S. president would have to consider very carefully the risks of intervening in a renewed Korean conflict, even if with only conventional weapons initially.

It is important to remember that the danger to the United States is derivative—that is, a result of the U.S. defense commitment to South Korea. Kim does not spend his time making idle threats against Europe, South America, Africa, or Asia, other than South Korea and Japan. He is challenging Washington because Americans are over there, threatening him with war. The issue isn’t whether U.S. policy is right or wrong. Rather, a North Korean nuclear program is the natural result of the U.S. presence in South Korea as well as its frequent support of regime change. After Iraq, Libya, and Syria, Kim would be a fool if he did not create and keep a sizable nuclear arsenal.

No one knows where the North Korean program might end. However, the Asan Institute for Policy Studies and the Rand Corp. warned in a 2021 policy paper that the North could amass up to 242 nukes as soon as 2027. That’s a controversial estimate, but anything in that range would solidly place North Korea among the second-tier nuclear powers, disrupt Asia’s traditional balance of power, and set off wailing and gnashing of teeth in Washington. U.S. policymakers would have to reconsider the mutual defense treaty’s value and the necessity of military decoupling.

Lest that seem extreme, what policy options does Washington have? The Biden administration has been reduced to essentially begging Pyongyang to talk. But it’s unclear what incentive there is for the North to do so. Kim has loudly and repeatedly dismissed negotiating away his nuclear arsenal, while the United States is still committed to the complete, verifiable, and irreversible denuclearization of the peninsula, known as CVID. The United States and North Korea are like ships passing in the night. There is much wishful thinking about convincing Kim that he need not fear the United States—a considerable challenge given the U.S. military’s active global role. Even if the United States actually doesn’t intend to attack the North, Kim would be a fool to base his future on such an assumption.

What to do? Washington needs to convince Pyongyang to engage, as well as indicate that it is worth engaging. Neither will be easy.

The United States should begin by ending policies that cannot help but look hostile. First, drop the ban on Americans traveling to North Korea. Announce that it is time for the American and North Korean peoples to engage with each other, drop the restriction, and encourage U.S. civil society to begin proposing small educational, cultural, and sporting projects. That comes with obvious risk, given the North’s record of seizing Americans—but a more open policy, and the status that comes with it, would make Pyongyang less likely to cross those lines.

Moreover, the administration should indicate its desire to demonstrate mutual respect and open a regular diplomatic channel. That could begin with liaison offices, but the objective should be full diplomatic relations.

Washington long has had the arrogant attitude that talking with other nations is a positive reward for them. That’s nonsense. It should be evident that refusing to engage with adversaries—for a time, the Soviet Union, China, and Cuba, as well as more recently Iran, Syria, Venezuela, and North Korea—is extremely foolhardy.

The lack of communication with Beijing in 1950 contributed to the U.S.-China clash in the Korean War. The two governments had no way to confront each other peacefully over China’s determination to prevent the allies from overrunning the North and ending up on the Yalu River. More recently, Washington was embarrassed by China’s mediation between Iran and Saudi Arabia, which was made possible by refusing to engage with Tehran.

It’s worth looking back at the early 1970s and Ostpolitik, which led to mutual recognition of West and East Germany. There were differences from the Koreas: The German Democratic Republic did not claim authority over all of Germany and was satisfied with acceptance of its more limited claim. However, tensions between the two relaxed as the process moved forward. Both states entered the United Nations; the Soviets and East Germans eased pressure on West Berlin; and East Germany felt challenged by the significant increase in cross-border traffic. Offering what Kim supposedly wants, easing the so-called hostile policy, would be a good test of his intentions.

The call for diplomatic ties should be twinned with a suggestion for an initial negotiating topic—a peace declaration leading to a formal treaty. The idea horrifies many policymakers. For instance, a gaggle of U.S. legislators, led by Korean American Rep. Young Kim, warned in 2021 that such a step would “destabilize security” and “cede the negotiating leverage” to the North. Of course, Pyongyang could have similar doubts. However, history is filled with a cold peace that lasted and sometimes even warmed up: France-Germany, Egypt-Israel, Iran-Iraq, and the United States-Vietnam, to name a few. Russia-Ukraine might eventually end up on that list.

Talking about peace would naturally include discussion of arms control. The allies should proceed without mention of CVID, neither affirming nor abandoning it. Successful arms control would move down a path that could, however unlikely, lead to full denuclearization. Expecting anything else would be the triumph of hope over experience, a dubious tactic when dealing with North Korea.

Any course to peace is very hard to see at present, but there’s no other way than beginning with these small steps. Neither side has any reason to trust the other. Neither side appears willing to take the kinds of steps necessary to generate such trust. So the Biden administration should propose that the main parties sit down and, first, agree that combat has ended and, second, create a framework for longer-term peace. To signal that it is willing to negotiate for something other than CVID, the United States should suspend some unilateral sanctions. If the effort came to naught, Washington could reinstate them, if desired.

There is no guarantee that such an approach would yield results. However, doing nothing is doomed to fail. Indeed, doing nothing ensures that the North will continue building nukes and refining intercontinental ballistic missiles. The day when U.S. cities become nuclear targets will grow ever closer.

Worse, doing “something, anything” could be worse, much worse. Preventive military action could trigger a full-scale war. Piling on more sanctions is unlikely to have any impact, given Chinese and Russian support of the North. Pyongyang survived after almost completely isolating itself to combat COVID-19 in recent years.

An engagement program would gain credibility if backed by a liberal U.S. president and conservative South Korean president. It also might convince Kim that there is some value in talking with Yoon as well as Biden.

Yoon’s visit to Washington is sure to be a celebration of the alliance. However, the U.S. promise to defend the South is a second best, a defensive response, not an affirmative good. Better to remove the claimed need for such a guarantee by attempting to find a peaceful modus vivendi for the Korean Peninsula. And that requires getting the parties to talk.

The Biden administration is running out of time, with a presidential election approaching, which likely will paralyze its decision-making. Kim also will have decreasing interest in dealing with a potential lame duck. Yoon’s approval ratings are low, and next year his party will be seeking to upend the opposition’s National Assembly majority. Today might not look propitious for a Korean deal, but if not now, when?

U.S. and South Korean policy toward the North has failed. The danger for Americans is increasing. Instead of celebrating their improved relationship, Seoul and Washington need to develop a new strategy for engagement with North Korea, before any chance is gone for good.