One year after the handshakes, photo ops and circus-like fanfare of the first-ever summit between a sitting U.S. president and a North Korean leader, hopes that Pyongyang will soon give up its nuclear weapons have all but evaporated.

Following the Singapore summit, and another one in Hanoi earlier this year, U.S. talks with the North to relinquish its nuclear arsenal have hit a wall due to major differences over the scope of North Korea’s denuclearization and potential sanctions relief by the United States.

U.S. President Donald Trump, in his quest to reach a deal with North Korean leader Kim Jong Un and write his name into the history books, has turned the process of negotiating with the nuclear-armed country on its head.

“The Trump approach has been, by normal standards, upside down,” said Joshua Pollack, a North Korea expert at the Middlebury Institute of International Studies. “It started with summits rather than working-level talks among professionals, with only brief prior interactions through a senior envoy.”

Pollack said that rather than rely on the precedent of a strong initial “agreement to disagree on certain points … Trump and Kim started with a superficial and vague agreement in Singapore, then collided over a hard disagreement in Hanoi.”

Bereft of timelines or concrete concessions from either side, the vaguely worded Singapore document actually contained far less substance than previous U.S. and multilateral agreements reached with the North.

The second summit in Hanoi did little to bridge that cavernous gap between the two sides.

Now, U.S. officials say that the North Koreans have not responded to their entreaties for talks since Hanoi. Instead, they’ve begun firing salvoes at the U.S. — hard-line public pronunciations against Washington’s “hostile policy” toward Pyongyang.

“Reasonable hopes that something more could be built on the Singapore joint statement have dissolved,” Pollack said.

And while Trump doesn’t seem to mind the status quo set by Kim, who has halted longer-range missile and nuclear tests, there are strong signals that the next six months will test the two leaders’ cozy relationship.

Trump has repeatedly touted the pair’s strong ties, but with North Korea delivering a wave of criticism over Washington’s position in the negotiations and Kim setting an end-of-the-year deadline for progress, the mercurial U.S. leader could soon change his tune.

In the latest in a spate of increasingly threatening warnings aired in the North’s state-run media, the country on Tuesday urged the U.S. to “withdraw its hostile policy” and abide by the pledges in the Singapore document.

“The arrogant and unilateral U.S. policy will never work on the DPRK, which values sovereignty,” the official Korea Central News Agency said, using the acronym for the North’s official name, the Democratic People’s Republic of Korea.

Tuesday’s warning was the sixth published by KCNA since April 20.

Last week, the North’s Foreign Ministry also warned the U.S. that if it did not “change its current method of calculation” in nuclear negotiations, it would risk turning last year’s Singapore joint declaration into a “mere blank sheet of paper.”

“There is a limit to our patience,” it ominously concluded.

Observers say, after the failure in Hanoi, the Foreign Ministry, which has traditionally been viewed as a body with little real power, now looks to be in charge of talks with the U.S.

“Considering the greatly stepped-up tempo of Foreign Ministry statements on the subject in 2019 compared to 2018, the U.S. portfolio does appear to have reverted to them,” said Pollack. “If by some stroke of good fortune talks do resume, I would expect senior Foreign Ministry officials to play a greater role than before.”

This shift also comes amid speculation of a possible internal power shake-up by Kim, with media reports claiming that some top officials, including Kim’s right-hand man, Kim Yong Chol, and his sister, Kim Yo Jong, had been sidelined. One report in South Korean media even went so far as to report on the alleged execution by firing squad of the North’s top nuclear negotiator.

The North is a well-known intelligence black hole, and some experts have said that these recent reports appear to be bogus.

“I think these stories are overblown. They play well in the international media, but they are thinly sourced,” said Ken Gause, a North Korea expert and director of the Adversary Analytics program at CNA, a nonprofit research and analysis organization.

In the case of Kim Yong Chol and Kim Yo Jong, he said, “they seem to have been off the mark,” as both were seen in photographs in state-run media shortly after the reports.

Gause said that by placing the Foreign Ministry in charge of negotiations, “Kim has normalized his diplomatic approach.”

Still, he noted, “Figures such as Kim Yong Chol, although they have been taken off the front lines of diplomacy, are likely still involved in helping develop the diplomatic strategy.”

This strategy is likely to be focused on maintaining a balance between continuing to nudge Trump on sanctions relief while trying not to push him too far.

“For the time being, Kim Jong Un plans to respect his unilateral pledge of April 2018 not to test intermediate-range ballistic missiles, intercontinental-range ballistic missiles, or nuclear devices,” Pollack said. “That leaves him with a number of options, if he cares to exercise them. Still, by the standards of the testing spree of 2014-17, the North Koreans have been pretty quiet.”

Pollack said this restraint would continue as long as Seoul or Washington refrain from actions Pyongyang considers threatening.

In the meantime, however, the North will continue to incrementally ratchet up pressure on Trump, threatening his crowning foreign policy achievement as the U.S. leader’s re-election bid ramps up.

So far, the U.S. president has managed to avoid any blowup of the status quo. He swatted away claims that the North had violated U.N. sanctions by testing short-range missiles last month, telling reporters that, though top White House officials had viewed them as violations, he saw things “differently.”

But Kim will assuredly be leery of angering the volatile Trump, not wanting to lose his golden goose. Trump has promised massive economic support in exchange for Kim relinquishing the country’s nukes, but experts say the North Korean leader would almost assuredly never part with his “treasured nuclear sword” in exchange for aid.

Rather, as he bides his time, Kim will likely bolster his own defensive and offensive weapons while slowly heaping pressure on the White House to return to the table.

“I expect that Kim will move slowly in terms of testing of critical defense systems in order to try to avoid passing a threshold of no return with the U.S.,” Gause said. “This means a gradual escalation of missile tests and rhetoric.

“He understands that Trump is an unconventional president and his only hope of getting sanctions relief anytime soon,” Gause added. “Therefore, he will be cautious in how he escalates in an effort to bring the U.S. back to the negotiating table.”

South Korean President Moon Jae-in said Monday that he believed talks between both Koreas and between Pyongyang and Washington would resume soon.

During a state visit to Finland, media reports quoted him as saying that talks were underway about a third summit between North Korea and the United States, “so I don’t think it’s a situation that needs a third country’s arrangement.”

Trump said last week he looked forward to seeing Kim at the appropriate time.

As for Prime Minister Shinzo Abe and his offer to meet with Kim “without conditions,” there’s little reason to believe that such a summit will happen in the near future.

Tokyo has been unable to directly propose arrangements for such a summit, including last week at a two-day security conference in Mongolia, where Pyongyang abruptly pulled its officials from the forum, further dampening hopes of a meeting.

Experts say there is little incentive at the moment for Kim to meet Abe.

“Abe will not be able to secure a summit with Kim under the current conditions unless he is willing to offer economic aid upfront,” Gause said. “Otherwise, Kim gains nothing from meeting with Abe, who will only lecture him on denuclearization and plead for the return of abducted Japanese citizens.”

Still, Pollack said that Tokyo “shouldn’t complain too much.”

“Japan’s entreaties to Washington — that ‘denuclearization’ be treated as equivalent to the full demands of the (U.N.) Security Council on North Korean nuclear weapons, missiles, chemical weapons, and biological weapons —is now also the U.S. position,” he said.

“They have every reason to be satisfied with the return to deadlock,” he added. “How pleased they will be with the outcomes as the deadlock continues is another good question.”