After U.S. President Donald Trump and North Korean leader Kim Jong Un met last June in Singapore for the first time, Trump declared on his way home "there is no longer a nuclear threat from North Korea."
"I have solved that problem," a triumphant Trump said three days after his summit with Kim.
But on Wednesday's one-year anniversary of the Singapore meeting, a nuclear deal seems more elusive than ever, with working-level talks stalled and public disagreements emerging among U.S. officials over how to respond to North Korea's provocations.
Trump remains publicly optimistic about his relationship with Kim. On Tuesday, Trump said he received another "beautiful letter" from the North Korean leader. He did not elaborate on the letter's contents other than to say it was "very warm," "very nice," and "very personal."
But there is little evidence Trump's personal relationship will convince Kim to abandon his nuclear weapons, which he has long viewed as crucial to preserving his rule.
"I think it's exactly where we were a year ago," said Darcie Draudt, a North Korea researcher and visiting scholar at Seoul's Yonsei University. "It's the actual day-to-day interactions, the on-the-ground, mid-level exchanges that are really going to do the work. And we really haven't seen that."
North Korean officials have gone silent since Hanoi, said Stephen Biegun, the U.S. special representative to North Korea, at an off-the-record briefing at the Korea Economic Institute in Washington last week, according to three attendees who spoke to VOA on condition of anonymity.
According to the attendees, Biegun said he recently sent a letter to North Korea's Vice Foreign Minister Choe Son Hui asking to resume working-level talks, but has received no response.
North Korea has also stopped cooperating on major inter-Korean projects, such as a joint North-South effort to recover the remains of soldiers who died in the 1950s Korean War.
Amid the stalemate, Washington and Pyongyang are again teetering on the edge of a period of hostility. North Korea last month restarted ballistic missile tests for the first time in almost a year and a half.
"Its nuclear and ballistic missile programs not only are left intact, they are also advancing and growing, since they were never bound to an agreement," said Soo Kim, a policy analyst at the RAND Corporation and a former CIA analyst.
In Singapore, Trump and Kim agreed to work "toward the denuclearization of the Korean Peninsula." U.S. officials later acknowledged Washington and Pyongyang do not share a common understanding of the word "denuclearization."
A February summit between Kim and Trump in Hanoi, Vietnam had been expected to at least lay out a path forward. But instead, the meeting underscored the breadth of disagreements between the two sides, with Trump leaving early and declaring Kim "not ready" to make a deal.
Trump has insisted Kim abandon his entire nuclear weapons program before the United States relaxes sanctions against the North. Kim wants an incremental approach that would see the U.S. ease sanctions gradually in exchange for limited steps to dismantle his nuclear program.
Cracks in US strategy
The Trump administration's strategy toward North Korea is increasingly marked by inconsistencies, if not outright contradictions.
Not only have U.S. officials given conflicting statements about whether they are open to a step-by-step denuclearization process, Trump at times openly disagrees with his top advisors over Korea policy.
After North Korea conducted several short-range missile and other weapons tests in early May, White House National Security Advisor John Bolton pointed out the launches violate United Nations Security Council resolutions.
"My people think it could have been a violation," Trump acknowledged, adding: "I view it differently. I view it as a man — perhaps he wants to get attention, and perhaps not. Who knows? It doesn't matter."
At various points over the last month, Trump has seemed to suggest the North Korean launches never happened. At other moments, Trump has said the tests were unimportant because the short-range missiles were not capable of hitting the United States.
The launches are a potential embarrassment for Trump, who has long pointed to a lack of North Korean missile and nuclear tests as evidence his talks with Kim are succeeding.
Stalemate to continue?
Trump regularly says he is in no rush to reach a deal with North Korea, insisting that Kim understands it is in his interest to give up his nuclear weapons.
But, North Korean officials continue to say the exact opposite, warning they will not give up their weapons unilaterally and setting an end-of-the-year ultimatum for the United States to change its approach.
"The arrogant and unilateral U.S. policy will never work on the DPRK, which values sovereignty," the official Korean Central News Agency said Tuesday, using an acronym for North Korea's official name.
The agreement signed by Kim and Trump in Singapore "is in danger of being a blank sheet of paper because the U.S. is turning a blind eye to its implementation," KCNA said.
"There is a limit to the DPRK's patience...now is the time for the U.S. to withdraw its hostile policy concerning the DPRK," it continued.
But it is in neither side's interest to dramatically escalate tensions, said Khang Vu, U.S. East Asia policy researcher and contributor to the Australia-based Lowy Institute think tank.
"Kim Jong Un understands that he can potentially benefit from sanctions relief and inter-Korean trade as long as he carries on with the denuclearization process, even through a vague commitment," Vu said.
Meanwhile, Trump may feel constrained by the upcoming 2020 presidential election season.
"The possibility of success is low, but as long as the U.S. and North Korea are interested in talking, Trump and Kim will not engage in another fire and fury,'" said Vu.
Trump to visit South Korea
It's unclear what will break the deadlock. One possible flashpoint: Trump's visit to South Korea at the end of June.
South Korean officials have said they are trying to arrange another meeting between President Moon Jae-in and Kim Jong Un ahead of Trump's visit.
Those comments, along with Kim's latest letter to Trump, are prompting some optimism in Seoul.
"Until yesterday, I was pessimistic," said Yun Ji-won, a professor at Seoul's Sangmyung University. "I expect it can be part of momentum for a third [Trump-Kim] summit."
Lee Juhyun contributed to this report.