TOKYO — U.S. envoy Stephen E. Biegun will travel Wednesday to meet his North Korean counterpart in Pyongyang, where he will try to advance a plan to reinvigorate denuclearization talks ahead of a new summit.

Many North Korea experts credit President Trump for opening a dialogue with leader Kim Jong Un after years of drift under President Barack Obama — a period when North Korea built up its nuclear and missile programs. But Trump has been criticized for not eliciting any firm commitment from Kim to begin the process of denuclearization when they met for the first time in Singapore in June. 

Trump, at his State of the Union address Tuesday, said that he will meet with Kim on Feb. 27-28 in Vietnam for the second summit. “As part of a bold new diplomacy, we continue our historic push for peace on the Korean Peninsula,” he said.

Since his appointment in August as special representative for North Korea, Biegun has played a central role in trying to put substance around what the United States wants and how it wants to achieve it. 

Initially frozen out by the North Koreans, he accompanied Secretary of State Mike Pompeo to meet Kim in October, and he met his newly appointed counterpart, Kim Hyok Chol, in Washington last month for what he called an “extended working-level discussion” that he said was “productive, focused, results-oriented.”

Biegun was initially expected to meet Kim Hyok Chol in the Korean border village of Panmunjom for a second time Tuesday, but his invitation to Pyongyang suggests that the North Koreans are taking him more seriously, experts said.

Last Thursday, Biegun set out for the first time in a speech at Stanford University how he hopes to move the denuclearization process forward, taking what several experts described as a more flexible and realistic approach than the administration has adopted thus far.

“His speech represents a genuine breakthrough in thinking about North Korea as a U.S. policy dilemma,” said John Delury, an associate professor at Yonsei University Graduate School of International Studies in Seoul.

Delury said he thinks the Trump administration is pursuing a radical shift in U.S. policy toward North Korea — advancing denuclearization as part of a larger process of fundamentally transforming relations between the two countries. It is a shift that Biegun is pushing “with a level of detail and thoughtfulness that is revelatory,” Delury said.

Biegun said the administration is ready to engage with North Korea despite “dramatically different views on individual rights and on human rights.” He said Trump is “deeply and personally committed to once and for all bringing an end to 70 years of war and hostility.”

In particular, Biegun said, the United States hopes to move “simultaneously and in parallel” with the North Koreans in implementing the pledges their two leaders made in Singapore, including denuclearization, transforming their relations and building lasting peace on the Korean Peninsula.

In the recent past, Pompeo and national security adviser John Bolton have given the impression that the United States wants North Korea to move unilaterally to completely surrender its nuclear arms and missile programs before obtaining sanctions relief. That led Kim Jong Un to warn in a New Year’s Day speech that he might be forced to follow a new path if Washington continued to insist that he move unilaterally while sanctions are maintained. 

Biegun has advanced a slightly more nuanced position. It was correct to say that sanctions would be lifted only when denuclearization is achieved, he said, but that is not the same as saying, “We won’t do anything until you do everything.” In other words, he suggested, there are steps the United States could take to build confidence in the meantime.

He reiterated that the U.S. administration wants to see a “comprehensive declaration” of North Korea’s “weapons of mass destruction missile programs,” but he said that should come “at some point” before complete denuclearization. 

Until now, the administration has been asking for a full declaration up front, which Pyongyang has resisted and the South Korean government has viewed as unrealistic.

Biegun also said that Kim Jong Un told Pompeo that he was prepared to dismantle and destroy all of North Korea’s plutonium and uranium-enrichment facilities at “a complex of sites” extending beyond the main, well-known complex at Yongbyon, provided that the United States takes “corresponding measures.”

That would extend the offer that Kim Jong Un apparently made when he met South Korean President Moon Jae-in last September, to dismantle Yongbyon. But experts said that because he has not made such an offer publicly, and because it is conditional on unspecified U.S. concessions, it was hard to know how seriously to take it.

Biegun also won praise from some North Korea watchers for acknowledging that both sides had made mistakes over the past 25 years of negotiations, a far cry from Washington’s usual position of blaming only Pyongyang, accusing it of cheating and perfidy. 

He also noted that in the Singapore summit, “there was no detailed definition or shared agreement of what denuclearization entails.”

Shin Beom-chul of the Asan Institute for Policy Studies in Seoul said it was a good sign that Washington is not hiding the divergence on this issue.

“President Trump was entrapped by North Koreans in Singapore after front-loading too many actions for that first summit,” he said. “The U.S. is taking a more realistic approach to the second summit, with clear demands and firm commitments.”

Mintaro Oba, a speechwriter at West Wing Writers and a former diplomat on the State Department’s Korea desk, said Biegun has taken “baby steps” in two key areas where U.S. policy had been severely deficient. He said the envoy is better managing public expectations and is “proactively defining a public narrative” on U.S. terms, instead of allowing Washington to be outmaneuvered by Pyongyang.

“By making a speech with a healthy amount of positive, public signals, Biegun took a step toward making the United States seem like it is actively trying to make progress and putting the onus on North Korea,” Oba said.

The question now is how the North Koreans will react. 

In the past, Pyongyang has given the impression that it was not interested in working-level talks and instead wanted to leave all the big decisions to Trump and Kim Jong Un — perhaps because the North Koreans thought Trump would be more easily outmaneuvered. But experts say it is unrealistic to expect success at the upcoming summit unless Biegun and Kim Hyok Chol prepare the ground in advance.

“U.S. and North Korean negotiators only have two or three weeks to form very important agreements,” said Junya Nishino, director of contemporary Korean studies at Keio University in Tokyo. “Actually, I don’t think there is enough time.”

Min Joo Kim in Seoul contributed to this report.