TOKYO — In announcing his decision to exit the Iran nuclear accord, President Trump said he also wanted to send a signal about the kind of hard bargain he plans to drive with another longtime American adversary, North Korea.

Many analysts in Asia greeted the move with skepticism, however, saying it would instead jeopardize the goals of a planned summit meeting between Mr. Trump and North Korea’s leader, Kim Jong-un.

By withdrawing from the Iran deal, analysts said, Mr. Trump has proved the United States to be an untrustworthy negotiating partner that cannot be counted on to honor any agreement. “Only a fool would trust the US to keep its word in a rogue state nuke deal now,” Robert E. Kelly, a professor of political science at Pusan National University in South Korea, wrote on Twitter.

If Mr. Trump wants to persuade North Korea to give up its nuclear arsenal, his decision could produce the opposite outcome.

“Yep, if you like a nuclear-armed North Korea, you are going to LOVE walking away from the Iran deal,” Jeffrey Lewis, director of the East Asia Nonproliferation program at the Middlebury Institute of International Studies, wrote on Twitter.

For its part, the Trump administration indicated that the decision was intended to show North Korea that only a complete rollback of its nuclear program would be acceptable.

“The message to North Korea,” John R. Bolton, Mr. Trump’s national security adviser, told reporters, “is the president wants a real deal.”

By using the pullout from the Iran deal as an implicit threat that Mr. Trump would walk away from the negotiating table if Mr. Kim does not agree to complete disarmament on an aggressive timeline, the administration “is setting a very high bar for success,” said Bruce Klingner, a Korean and Japanese specialist at the Heritage Foundation in Washington.

In a way, said Mr. Klingner, Mr. Trump has “painted himself into a corner diplomatically and reduced his flexibility because the deal has to be better than anything that came before.” What’s more, he said, “Democrats and proponents of the Iran deal will be assessing any deal that Trump comes up with against the Iran deal.”

But Mr. Trump’s propensity to reverse course — sometimes even within the space of a day — could also allow him to portray whatever deal he does achieve as a success. “He can get out of that corner by declaring that whatever you agree is the best and fulfills all the requirements, even if it doesn’t seem to,” Mr. Klingner said.

If Mr. Trump presents Mr. Kim with a stark demand to dismantle the North’s nuclear arsenal completely and quickly, “it challenges Kim Jong-un to decide whether he can accept the kind of deal the Trump administration insists on,” said Moon Seong-mook, a senior analyst at the Korea Research Institute for National Strategy in Seoul, South Korea. “It will test how desperate and how sincere Kim Jong-un is for a deal.”

In recent weeks, Mr. Kim has not been behaving like a desperate leader. Whereas he spent the first six years of his reign as a recluse, never venturing outside the country, he has been to China twice in 40 days to meet with President Xi Jinping, and last month traveled to the South Korean side of the border village of Panmunjom to meet with President Moon Jae-in. China, the North’s longstanding patron, had at first seemed sidelined from the talks, but now could potentially play a significant role in whatever deal emerges.

During that historic summit meeting, Mr. Kim and Mr. Moon delivered a statement committing to the denuclearization of the Korean Peninsula, though they gave few details about what that meant.

Indeed, while the term has been bandied about regularly in a frenzy of diplomacy in recent weeks, denuclearization is a fungible concept.

During a meeting in Tokyo of the leaders of China, Japan and South Korea on Wednesday, all three mentioned “denuclearization” during remarks to reporters. Yet it is clear they have different ideas about how it would be achieved.

On Tuesday, for example, when Mr. Kim flew to Dalian, China, to meet with Mr. Xi, the two leaders outlined a far more drawn-out process for denuclearization than is favored by either the United States or its ally Japan.

Denuclearization is “a very broad Rorschach test” that can “mean anything and everything to everybody,” said Kent Calder, director of the Center for East Asian Studies at the Johns Hopkins School of Advanced International Studies in Washington.

In a meeting between Mr. Moon and Mr. Abe on Wednesday, the South Korean leader emphasized the challenges of agreeing on definitions and developing a road map for achieving North Korea’s disarmament. “While North Korea has agreed on the basic principle of denuclearization,” Mr. Moon said, “it is a difficult question how to specifically realize that.”

Mr. Trump is known for his impatience. And some analysts said Mr. Kim might shrewdly seize on the decision to withdraw from the Iran deal as a reason to offer shallow, short-term concessions, on the basis that the United States cannot be trusted to enter a long-term deal.

“Kim Jong-un is choreographing this diplomatic dance, and seems to have studied Trump carefully,” said Laura Rosenberger, a senior fellow and director of the Washington-based Alliance for Securing Democracy. “The erosion of U.S. credibility by pulling out of the Iran deal reduses the incentives for Kim to agree to a long-term deal and increases incentives for him to dupe Trump into something that sacrifices U.S. interests but allows Trump to declare victory and go home.”

In Japan, analysts said Mr. Kim had already accounted for Mr. Trump’s desire for quick wins, even before the withdrawal from the Iran deal. “North Koreans will continue to maintain their tactics,” said Kunihiko Miyake, a former Japanese diplomat now teaching at Ritsumeikan University in Kyoto. “The real question is whether or not the Americans will buy it.”

In calling for more stringent demands that North Korea dismantle its weapons program, Mr. Bolton appeared to raise the stakes for Mr. Trump’s meeting with Mr. Kim. Analysts in China suggested Mr. Kim had no intention of giving up his nuclear weapons. “At the end of the day, Kim Jong-un is not planning to trust the U.S. security guarantees,” said Tong Zhao, a fellow at the Carnegie-Tsinghua Center for Global Policy.

Mr. Trump’s withdrawal from the Iran deal, Mr. Tong said, proved to North Korea that American guarantees “can be reversed anytime.”

“Retaining his core nuclear capabilities serve as a hedge against future uncertainties,” Mr. Tong said.

By engaging in a whirlwind of diplomacy, Mr. Kim has deftly sought to play countries off one another. His trip to Dalian, China, this week was part of his effort to enlist Beijing’s support in confronting the American pressure while taking advantage of “the struggle for regional hegemony between China and the United States,” said Yun Duk-min, a former chancellor of the Korea National Diplomatic Academy in Seoul, who now teaches at Hankuk University of Foreign Studies.

All of North Korea’s neighbors are hustling to stake their own claims to guiding the peace process on the peninsula.

“Under the rubric of ‘we need to solve this proliferation problem,’ they are each angling to enhance their own prestige vis-à-vis the other,” said June Teufel Dreyer, professor of political science at the University of Miami. “They are all trying to solve it in a way that allows them to take the credit while not adversely affecting their own interests.”

Amid all this wrangling, North Korea may have the least to lose.

Even if the meeting between Mr. Kim and Mr. Trump does not produce an agreement, said Duyeon Kim, visiting senior fellow at the Korean Peninsula Future Forum in Seoul, “the North doesn’t lose much because it can continue business as usual by refining and mass producing nuclear warheads and ballistic missiles as planned.”