WASHINGTON — Over the past six weeks, the Trump administration’s roster of Korean experts, already depleted, grew even thinner. The White House mysteriously dropped its choice for ambassador to Seoul. The State Department’s top North Korea specialist resigned. And the senior Asia director at the National Security Council was out the past two weeks on paternity leave.

But when a high-level South Korean delegation arrived at the White House on Thursday afternoon for two days of meetings over the North Korea threat, one person swooped in to fill the vacuum: President Trump.

In a stunning turn of events, Trump personally intervened into a security briefing intended for his top deputies, inviting the South Korean officials into the Oval Office where he agreed on the spot to a historic but exceedingly risky summit with North Korean dictator Kim Jong Un. He then orchestrated a dramatic public announcement on the driveway outside the West Wing broadcast live on cable networks.

The news shocked Washington, Seoul and everywhere in between. But inside the White House, the president – whose exchange of taunts and threats with Kim had set northeast Asia on edge over a potential military confrontation for months – was said to be reveling in his big reveal, which overshadowed the growing scandal surrounding his alleged affair with a pornographic film star and concerns with tariffs he announced earlier in the day.

“The president is the ultimate negotiator and dealmaker when it comes to any type of conversation,” says his press secretary. Bloomberg/Andrew Harrer

AN ENORMOUS GAMBLE

Trump’s personal involvement in the White House’s deliberations over the world’s most serious and vexing security situation has now placed a president who considers himself a master dealmaker into the most fraught faceoff of his 71 years. A breakthrough that would reduce Pyongyang’s nuclear threat would be a legacy-defining achievement. A stalemate that gives Kim a photo op for nothing in return could fracture U.S. alliances and be seen as a devastating embarrassment.

But what the whirlwind evening at the White House also illustrated was that in his unorthodox presidency, which centers so singularly on his force of personality, Trump has little worry about a dearth of qualified staff because he considers himself to be his own diplomat, negotiator and strategist.

“The president is the ultimate negotiator and dealmaker when it comes to any type of conversation,” White House press secretary Sarah Huckabee Sanders said. “And we feel very confident in where we are.”

The question is, where exactly is the Trump White House – and how did it get there?

The answer wasn’t clear Friday as Trump aides struggled to explain whether concrete steps from Pyongyang toward denuclearization were a precondition ahead of the summit, what the agenda of the talks will encompass and how a president known to disdain dense briefing books intends to prepare for an adversary that U.S. intelligence officials don’t know much about.

In fact, it was not the details of the planning process but rather Trump’s impulsive, improvisational style that was the biggest selling point as top aides fanned out to explain why the president had taken this enormous gamble. Asked why the administration did not engage in lower-level talks with the North to build out preconditions and an agenda for a leaders-level summit, one senior aide offered that Trump “was elected in part because he is willing to take approaches very, very different from past approaches and past presidents.”

Across Washington, foreign policy experts tried to make sense of the news, with many betting that the talks would not happen after the Trump team heard negative feedback from Tokyo, conservatives in Seoul opposed to President Moon Jae-in’s liberal government and some in Congress who fear the move is too rash.

JAPANESE BLINDSIDED

The Japanese, who have been wary of offering Kim a propaganda platform, were blindsided by the news. Diplomats at the Japanese embassy in Washington, gathered for a goodbye party for Ambassador Kenichiro Sasae on Thursday evening, scrambled to react when the news broke.

Trump hastily called Prime Minister Shinzo Abe and invited him to visit the White House in April to confer before the summit with Kim, which officials said would be held in May.

“Nobody thinks the North Koreans are serious in Japan,” said Michael Green, the NSC’s Asia director under President George W. Bush, who is meeting with officials in Tokyo this week. “Given how he blindsided the entire national security team … I would bet this does not happen.”

The South Koreans, who have fretted over Trump’s saber-rattling over the past several months, landed at Dulles International Airport midmorning Thursday. Perhaps battling jet lag after the 13-hour flight, they arrived at the White House in early afternoon for what they thought was the warmup act: a meeting with Trump’s top aides, including Defense Secretary Jim Mattis, Deputy Secretary of State John Sullivan and Director of National Intelligence Daniel Coats.

‘AN ART OF A TEASER’

Led by South Korea’s national security adviser, Chung Eui-yong, the delegation’s aim was to debrief Trump’s team on the four-hour meeting Chung held with Kim in Pyongyang shortly after the Olympics, which had provided the two Koreas a chance to reopen a long-dormant diplomatic dialogue.

But what was supposed to be an hourlong briefing took an unexpected turn when Trump himself intervened midway through. The Koreans had been scheduled to see Trump on Friday, but the president had gotten wind of the meeting and told aides he wanted to get involved immediately.

In the Oval Office, Chung explained to Trump that he had brought with him a personal invitation from Kim for a meeting – a stunning offer given Kim has not met with any foreign heads of state since assuming control of the North after his father’s death in 2011.

Chung later told associates that he believed the South Koreans had a strong hand to play with Trump. The North Korean leader had agreed that joint U.S.-South Korean military exercises, which had been delayed during the Olympics, could resume. And Kim pledged that the North would not take provocative actions, including missile tests, ahead of the summit.

The risks of such a meeting, however, were well known on the U.S. side: The North has violated past agreements to freeze its nuclear program in exchange for sanctions relief and no sitting American president has met with a North Korea leader over fears of being set up for failure.

Earlier this week, Vice President Mike Pence, who was supposed to meet with North Korean officials during the Olympics to deliver a hard-line warning, vowed that the administration’s “posture toward the regime will not change until we see concrete steps toward denuclearization.” On Thursday, Secretary of State Rex Tillerson, traveling in Africa, told reporters the administration was “a long ways from negotiations.”

In the Oval Office, some of Trump’s aides raised concerns, according to a person familiar with the discussion. But Trump, seated in an armchair next to Chung, with their aides arrayed on couches, dismissed their fears and “made the decision” on the spot.

Korea experts were dumbstruck by Trump’s impulsiveness.

“He’s much more of a TV personality than business person,” said Christopher Hill, who led the U.S. delegation in the Six-Party talks with the North during the Bush era that produced a weapons freeze that Pyongyang later violated. “This is not the art of a deal here – it’s the an art of a teaser.”

SHOW TIME IN WHITE HOUSE DRIVEWAY

The South Koreans, stunned they had gotten done in 45 minutes what they thought might take weeks, prepared to depart. But a White House aide asked them to stay because Trump, always aware of the production value of such a moment, had an additional request: Would they help draft a statement and read it to the press outside the West Wing?

Over nearly two hours, the two teams collaborated on a brief statement. Meantime, Trump popped his head into the White House briefing room – where he has never made remarks since taking office – and told reporters that the Koreans would be making a “major announcement” at 7 p.m.

A large group of reporters, which had spent most of the day focused on Trump’s morning announcement of new tariffs on steel and aluminum, assembled on the West Wing driveway at the “sticks”– journalist lingo for the bank of television microphones set up in case of impromptu press statements from White House visitors.

Shortly after the hour, with cable networks talking live to reporters in the driveway, a Marine guard opened the doors of the West Wing and Chung emerged, flanked by Suh Hoon, South Korea’s intelligence chief, and Cho Yoon-je, the South Korea ambassador to Washington. It was dark out and the camera lights cast a harsh light onto the officials.

Chung delivered the news in a 245-word statement. He took no questions.

The cable stations turned quickly to their analytical panels. Diplomats lit up international phone lines. And White House aides praised the president for his artful turn from bellicosity to diplomacy.

“That’s a decision the president took himself,” Tillerson said Friday. “This is something that he’s had on his mind for quite some time, so it was not a surprise in any way.”