Here’s hoping the Winter Games lead to a thaw in Korea

Politics always mixes with sports at the Olympics, but as the quadrennial Winter Games open in South Korea, the stakes are as high as they have ever been.

After months in which President Trump and the North Korean leader, Kim Jong-un, have escalated their angry words and the risk of nuclear war, the South Korean president, Moon Jae-in, is using the Olympics to reopen long-dormant contacts with the North and possibly establish a formal channel of communication with Mr. Kim.

Athletes are participating in this diplomatic pas de deux; the South Koreans and North Koreans will be marching side by side in the opening festivities on Friday and playing jointly for the first time on the women’s ice hockey team.

Top Trump administration officials, and many experts, doubt that anything serious will come of the South Korean initiative. They think it will just help North Korea engage in a charm of- fensive while it presses against sanctions and refuses to give up its nuclear program.

But the outreach is necessary and courageous. Mr. Moon, elected last year on a promise to improve ties with North Korea, will deserve credit if his efforts help reduce the North Korean threat.

One good sign is that Mr. Moon has persuaded key foreign officials to attend the Olympics opening ceremony and thus be in proximity in case diplomatic fairy dust creates an opportunity for interaction. Not only are Prime Minister Shinzo Abe of Japan and Vice President Mike Pence expected to show up, but also two senior North Korean officials: Mr. Kim’s sister, Kim Yo-jong, the first immediate member of the North’s ruling family ever to set foot in the South, and Kim Yong-nam, the country’s nominal head of state.

On Saturday, Mr. Moon plans to host the North Korean delegation for lunch

with the goal of restoring a high-level dialogue between the two countries after a hiatus of more than two years and of opening the door, maybe later this year, to a meeting between himself and Mr. Kim.

At a minimum, the lunch provides an opportunity for Mr. Moon to make clear directly to the North Korean leaders the risks and costs of failing to ease tensions, fueled mainly by the North’s accelerated push to develop its arsenal of nuclear warheads and the missiles with which to deliver them. North Korean officials have a hard time reading political signals from Washington, so frank discussions are crucial.

Whether Mr. Pence or Mr. Abe are open to even a brief discussion with the North Koreans is unclear. They have taken a much tougher stance against North Korea than Mr. Moon, creating a dangerous gap among the allies. En route to South Korea, Mr. Pence sent mixed signals, suggesting on Monday that he might be open to a meeting, then on Wednesday announcing plans to impose the toughest sanctions yet on the North over its nuclear and missile programs.

He told The Washington Post that “when the Olympics are long a distant memory,” the administration hoped “to continue to isolate North Korea economically and diplomatically.”

Mr. Pence will attend the Games with the father of Otto Warmbier, the University of Virginia student who was imprisoned by North Korea, then died suddenly when he was returned to his family last year.

Any contacts would be complicated by the fact that Ms. Kim is under American sanctions for her role in North Korea’s human rights abuses.

No matter how difficult it will be to peacefully resolve the North Korean nuclear crisis, the United States and its allies need to exhaust all diplomatic options. The administration must do more to coordinate with South Korea and treat this vital ally with respect.

This is at last a moment of sanity in what has been a problem hurtling toward a military confrontation. If nothing comes of South Korea’s initiative, the United States is likely to resume military exercises and the North is likely to resume nuclear and missile testing, touching off another escalatory spiral. Nothing good can come of that, given Mr. Trump’s threat to rain “fire and fury” on North Korea, and Mr. Kim’s threat to strike the United States with a nuclear weapon.

Mr. Trump can continue to apply “maximum pressure” against the North and still help Mr. Kim’s pursuit of engagement.