First the nuts and bolts: How do you protect what many North Koreans consider their single most precious resource, the third member of the Kim family to rule and a direct descendant of North Korea's worshipped founder Kim Il Sung?
The world is crossing its fingers.
Trump has also raised the possibility of further summits.
Boo Seung-chan, a research fellow at South Korea's Yonsei Institute for North Korean Studies, told the Post both sides were likely "focusing their energy on... setting a timetable for CVID and CVIG".
Mr Trump has said it normally takes him about five seconds to figure out whether he will get along with someone.
The only logical explanation for Rodman's visit to Singapore would have to do with the fact that he has been closely associated with Jong Un and Trump in the past.
Trump and other top USA officials have promised a "bright future" for the North if it quickly relinquishes its nuclear weapons - including economic inducements and a security agreement.
It has been used before for high-profile diplomatic occasions.
"I feel that Kim Jong Un wants to do something great for his people and he has that opportunity". As a master dealmaker, he'll just know.
Trump, seen here arriving in Singapore, has said his goal is denuclearization of North Korea. "But they just stopped right before they crossed that line".
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Kim's summit with Trump has captured intense global attention after a turn to diplomacy in recent months after serious fears of war previous year amid North Korean nuclear and missile tests.
Trump was greeted by Singapore Foreign Minister Vivian Balakrishnan.Asked by a reporter how he felt about the summit, Trump said: "Very good". He also referred to Mr Kim as "little rocket man".
The cancelled meeting was ultimately resurrected, and now the pair are less than a day away from holding historic talks.
Before Monday, official news outlets had reported only that the two leaders planned to meet, without saying where or when or offering any other specifics. The stakes for our nation are simply too great.
South Korea's Hankook Ilbo reported that Singapore recommended the St Regis, which hosted Chinese President Xi Jinping during his 2015 summit with Taiwanese President Ma Ying-jeou, because it can be easily secured. This isn't like the United States and Iran.
Japanese Prime Minister Shinzo Abe visited the White House this week to press Trump once more before the summit on those issues.
At the same time, Trump stressed that Washington would not accept Pyongyang's refusal to denuclearize.
Fifth, photo opportunities must be encouraged, not dismissed.
The understated photo op belied the intensive behind-the-scenes negotiations that continued between the US and North Korean delegations less than 24 hours before Trump was scheduled to meet Kim at the Capella Hotel on the resort island of Sentosa, just off Singapore's southern coast.
North Korea is estimated to have up to 120,000 political prisoners in its sprawling gulag system. For starters, we need to be realistic about what "success" means. "You don't know. This has not been done before at this level".
Suzanne DiMaggio, director and senior fellow at New America, said a statement on denuclearization is the best that can be hoped for at this point.