South Korean President Moon Jae-in, left, and President Trump meet at the White House on May 22. (Yonhap/EPA-EFE/Shutterstock)

Secretary of State Mike Pompeo on Wednesday offered no clear road map to reopening nuclear negotiations with North Korea nearly six weeks after the collapse of the Hanoi summit, leaving the Trump administration with dwindling options to salvage the talks.

Pompeo has said in recent weeks that he expects President Trump to have a third summit with North Korean leader Kim Jong Un, again dangling a prize to keep the once-isolated dictator engaged in diplomacy. But at a Senate Foreign Relations Committee hearing, Pompeo struggled to answer basic questions, including whether the two sides have agreed on a definition of complete and verifiable “denuclearization.”

“I can’t answer that question yes or no,” Pompeo told Sen. Ben Cardin (D-Md.). “We’ve had extensive conversations with North Korea about” that question.

When Cardin noted the North had yet to turn over an accounting of its nuclear arsenal, Pompeo replied: “There is still a great deal of work to do.”

Pompeo’s testimony came a day before South Korean President Moon Jae-in is set to visit Trump on Thursday at the White House for a meeting that could expose fault lines between the allies, who have collaborated closely since Trump’s first summit with Kim in Singapore in June.

Seoul was blindsided by the failure of the Hanoi summit to produce a modest deal that could help bolster inter-Korean economic relations — a potentially small but symbolic step that Moon’s government had hoped would help build trust for bolder action.

Instead, there have been no working-level meetings between the United States and North Korea since then, and Trump told reporters in late March that he had not spoken with Kim since the summit.

Democrats pressed Pompeo over whether the administration was being manipulated. Although the North has not tested a nuclear weapon or ballistic missile since November 2017 — a moratorium Trump has hailed as a sign of success — nuclear experts have said Pyongyang continues to secretly refine and expand its arsenal.

The North also rebuilt a missile and satellite launch station it had partially dismantled last year as a goodwill gesture, although experts have said there have been no signs that the regime is planning a new weapons test.

“My perspective is that Kim merrily rolls along with development of his nuclear program,” Sen. Jeff Merkley (D-Ore.) told Pompeo at the hearing. “I see Kim Jong Un trying to play out the string until the end of your administration with absolutely no results that can be pointed to in reducing the nuclear threat.”

Pompeo defended the administration’s actions. Countering suggestions from lawmakers that economic sanctions on the North are faltering, Pompeo said: “You should move to the outskirts of Pyongyang, because those folks think it’s very effective.”

Trump has continued to frame his North Korea strategy as a success. On Tuesday, the president posted a 2020 campaign video on his Twitter feed that included footage of him shaking hands with Kim. (The clip was removed over copyright infringement issues because it included music from a Batman movie.)

Behind the scenes, however, administration officials have said Trump’s negotiating team, led by Stephen Biegun, the State Department’s special representative for North Korea, has had little communication with Pyongyang.

The U.S. side has sent the message that it is prepared to resume working-level talks, but the negotiators have heard “nothing back,” said one Asia policy expert in Washington who was briefed by administration officials. The expert, who spoke on the condition of anonymity to discuss private conversations, added that the Trump team is running out of time.

“Realistically, if we’re not in a serious negotiation process by this summer, this will collapse, and then you’re in the 2020 [campaign] cycle,” the expert said, adding the North probably will want to wait to see whether Trump wins reelection. “We have about three or four months to get sustainable traction and momentum. They may do it, but I see no reason to think they’re going to get there.”

Trump ended his talks with Kim abruptly in Hanoi, asserting that the North Koreans demanded broad sanctions relief in exchange for the partial shutdown of its Yongbyon nuclear processing facility. Kim aides said the U.S. team refused to budge from insisting that the North shutter its entire nuclear program before any sanctions are lifted.

Moon is hoping to persuade Trump to be more flexible as a way to get the two sides talking again, analysts said. Among other things, Seoul has sought permission from the United Nations to reopen the Kaesong industrial zone inside the North that was closed in 2016.

Three weeks ago, a day after the Treasury Department had announced new economic sanctions on two Chinese shipping companies suspected of doing business with North Korea, Trump wrote on Twitter that he was withdrawing sanctions, prompting confusion inside and outside the administration over what he meant. Officials later said that the directive only applied to future sanctions. White House press secretary Sarah Sanders said the president acted out of respect for his good personal relationship with Kim.

At the Senate hearing Wednesday, Pompeo also appeared to offer a bit of wiggle room on sanctions relief.

“I want to leave a little space there,” he told the lawmakers. “From time to time, there are particular provisions, if we are making substantial progress, where one might think it’s the right thing to do . . . But yes, the enforcement regime, the core U.N. Security Council resolutions, need to remain in place.”