It was on, then off, then on again.
Now, the highly anticipated summit meeting between President Trump and the North Korean leader Kim Jong-un looks set to go ahead on Tuesday, with delegations from both sides in place.
Here is what to know before the historic meeting — the first between a sitting American president and a North Korean leader.
Where are the leaders meeting?
Sentosa, a tropical resort island south of Singapore’s main island, will be transformed into a heavily policed security zone from Sunday until Thursday, as it plays host to the summit meeting and the hordes of journalists who will be covering it. The island is home to luxury resorts, private marinas and a sprawling golf course.
The two leaders and their delegations will meet at the Capella Singapore. Mr. Trump and Mr. Kim are staying in two separate hotels elsewhere in Singapore — Mr. Kim at the St. Regis Hotel, and Mr. Trump less than a half a mile away at the Shangri La Hotel.
The host country, Singapore, will be responsible for security in the public spaces around the island and on roads leading to and from the meeting, while the United States and North Korea will oversee the safety of their leaders. Sentosa is connected to the mainland of the city-state by a causeway, a cable car and a monorail.
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Singapore’s government has designated a security zone around the entirety of the island, giving police the right to stop and search people at will.
A long list of substances and devices are banned within the security perimeter including drones, aerosol spray cans and flares. Singapore’s Maritime and Port Authority will also be restricting the movement of ships in the area and vehicles will be subjected to additional security checks, according to a statement from the Singapore police.
Who will be there?
In addition to Mr. Trump and Mr. Kim, who both arrived in Singapore on Saturday, each country will bring a delegation to the summit meeting, though the full list of who is taking part has not been released.
Two members of the president’s cabinet — Secretary of State Mike Pompeo and National Security Adviser John R. Bolton — will be there, according to the White House.
Mr. Pompeo has taken the lead with North Korea in preparing for the meeting. Earlier this year, he twice visited Pyongyang, the North’s capital, to meet with Mr. Kim and help lay the groundwork.
He was also in the room when Mr. Trump met with a top North Korean official, Kim Yong-chol, at the White House earlier this month, and was alongside the president when he announced the summit meeting would, in fact, go ahead after being abruptly called off days earlier.
The meeting was nearly derailed after Mr. Bolton made comments suggesting North Korea should follow a “Libya model” for disarmament. Those comments drew ire from Mr. Kim, and Mr. Bolton was mentioned by name in the first of two strongly worded rebukes from the North Koreans that preceded Mr. Trump’s decision to walk away from it.
Since making those comments, Mr. Bolton has been taking a back seat in the negotiations, but the White House insists he is not being sidelined.
On the North Korean side, little is known about who will attend. But Kim Yong-chol, the former head of North Korea’s spy agency and a four-star general, has been at the center of the preparations and will certainly be there.
A close aide to the North Korean leader, he is also the country’s lead nuclear arms negotiator and became the first North Korean official to set foot in the White House since 2000, when he met with Mr. Trump there last week.
While in Washington, he hand-delivered a letter from Mr. Kim that Mr. Trump described as “a warm letter” expressing interest in the summit meeting. It was shortly after his arrival that Mr. Trump announced the talks were back on.
Dennis Rodman, the former N.B.A. star, tweeted on Friday that he will be flying to Singapore for the summit. “I’ll give whatever support is needed to my friends, @realDonaldTrump and Marshall Kim Jong Un,” he tweeted.
But when asked if Mr. Rodman was invited, Mr. Trump made it clear he was not.
“But I like Dennis,” he told reporters before his departure.
What’s on the agenda?
Very little is known about the agenda, but Mr. Trump has said he didn’t think he had to do much to prepare, and that “attitude” was more important.
The first meeting between the two leaders is scheduled for Tuesday at 9 a.m. Singapore time — Monday at 9 p.m. East Coast time — according to the White House.
Mr. Trump has made clear that his goal is denuclearization.
“This will not be just a photo-op,” Mr. Trump said last Thursday during a news conference after Prime Minister Shinzo Abe of Japan visited the White House. “They have to de-nuke. If they don’t denuclearize, that will not be acceptable.”
But Mr. Trump noted that negotiations on denuclearization would take more time. “It’s not a one meeting deal,” he said.
Mr. Kim has expressed willingness to talk about denuclearization, but has revealed little about his own plans.
In recent months, Mr. Kim has rebranded himself from an international pariah and tyrannical leader who ordered his own half brother executed to a smiling statesman, meeting with the leaders of China and South Korea. But it is unclear if his willingness to denuclearize is simply a negotiating tool to pursue other goals.
Both leaders have proved unpredictable in the past, so it is unclear what, if anything, they will be able to agree on. Some have speculated that the summit could be extended an additional day, but Mr. Trump is currently set to leave Singapore on Tuesday evening.
On Thursday, just days before the summit, Mr. Trump was optimistic the meeting would be “a great success,” but said he would be willing to walk away if things didn’t go as planned. But if the meeting goes well, he said, he would invite Mr. Kim to the White House.
He said he hoped to normalize relations between the two countries and would consider signing a peace agreement to officially end the war on the Korean Peninsula.
“We are talking about it with them,” Mr. Trump said. “Sounds kind of strange but that could be the easy part.”