U.S. President Donald Trump agreed to hold a second summit with North Korean leader Kim Jong Un at the end of February. What the two leaders actually hope to achieve remains a mystery.

The announcement of a summit came after a 90-minute meeting at the White House on Friday between Trump and Kim Yong Chol, one of the North Korean leader’s top aides. They discussed “denuclearization and a second summit,” White House spokeswoman Sarah Sanders said. State Department spokesman Robert Palladino called talks that Kim Yong Chol had before and after the White House visit with Secretary of State Michael Pompeo “good.”

Aside from those bare-bones descriptions, the administration had nothing to say about the substance of the day’s meetings or what would be gained from a second summit.

The lack of details only raised new questions, particularly because so little progress has been made toward the ultimate U.S. goal -- getting North Korea to give up its nuclear weapons -- since the first summit between Trump and Kim in Singapore in June.

“I don’t think we have any concrete agreement,” said Sue Mi Terry, a former CIA analyst who’s now at the Center for International and Strategic Studies in Washington. “Obviously Kim doesn’t want to meet with the bureaucrats who would make him agree to something, and I think Trump would welcome the distraction right now.”

While Trump has credited Kim’s decision to halt weapons tests and dismantle a few testing facilities with preventing a war in Asia, those moves haven’t stopped North Korea from continuing a nuclear program that puts the U.S. and key allies at risk.

Satellite-imagery analysis and leaked American intelligence suggest North Korea has churned out rockets and warheads as quickly as ever in the year since Kim halted weapons tests and paved the way for his first meeting with Trump. One arms control group estimated Kim has gained enough fissile material for about six more nuclear bombs, bringing North Korea’s total to enough for between 30 and 60.

Trump’s decision to go ahead with another in-person meeting -- further elevating Kim’s global profile -- underscores the president’s confidence that his personal involvement and negotiating skills can change the behavior of recalcitrant regimes in ways that traditional leverage and diplomacy, past U.S. leaders and his own emissaries couldn’t.

In speeches, state media commentaries and meetings with his Chinese and South Korean counterparts, the once-reclusive North Korean leader has laid out a list of demands to break the deadlock in nuclear talks. His agenda ranges from restarting economic projects frozen by sanctions to formally ending the 1950-53 Korean War to weakening the U.S.-South Korean military alliance.

Stumbling blocks to a second summit have been North Korea’s insistence that it get relief from crippling economic sanctions, and Pyongyang’s demands that any disarmament deal with Trump include the removal of America’s nuclear-capable planes and warships from the region. That’s the North Korean interpretation of the pledge at the previous Trump-Kim summit to work toward “denuclearization of the Korean Peninsula.”

‘Nibble Around the Edges’

One possible solution would be what South Korean officials call “corresponding measures” to reward North Korean steps toward shedding its nuclear arsenal. The U.S. could, for example seek, the destruction of the Yongbyon nuclear processing site, while allowing some trade between North and South Korea to be exempted from sanctions. Other possible options could include a North Korean promise to stop producing new fissile material, or a peace declaration bringing a formal end to the 1950-53 Korean War.

But none of those would tackle the American objective: getting North Korea to give up its nuclear weapons for good, and allowing international inspectors to verify that it’s done so.

“There are ways that they can nibble around the edges,” said Jung Pak, a senior fellow at the Brookings Institution. “There are things on the periphery that they can talk about that will advance some goals and keep the ball moving on diplomacy. But we’re still locked horns on the nuclear issue.”

The next few days may help reveal how successful the summit will be. If today’s talks went well, the U.S. special representative for North Korea, Stephen Biegun, had planned to travel to Stockholm to meet his North Korean counterpart. The State Department wouldn’t immediately confirm if that trip will take place.

‘Real Progress’

Analysts have long been on the lookout for talks between the two envoys as a sign that the two sides were finally getting down to detailed discussion toward specific agreements.

“That would be real progress,” said Vipin Narang, a political science professor at the Massachusetts Institute of Technology. “We give up swinging for the fences and just get on base. There question is whether there’s enough time between now and February to hammer our the details.”

Trump has long signaled his interest in a second meeting with Kim, and there’s been speculation a summit could take place in Vietnam. U.S. officials met their North Korean counterparts in Hanoi for discussions to adjust scheduling for the talks, the South Korean newspaper Munhwa Ilbo reported.

Vietnam is a long-standing ally of Pyongyang that has good relations with Washington. Speculation about the country’s prospects as a summit site grew after North Korean Foreign Minister Ri Yong Ho’s visit there from Nov. 29 to Dec. 2.

Hanoi -- about a four-hour direct flight from Pyongyang and in airspace over countries friendly to North Korea -- boasts several world-class hotels. Vietnam’s ruling Communist Party also has the security apparatus to squelch protests and keep curious onlookers far away from Trump and Kim.