He made the threat after reports that Pyongyang had succeeded in building a nuclear bomb small enough to fit inside an intercontinental ballistic missile. And now, a face-to-face meeting.
The expected Kim-Trump meeting is considered unique given it'll be the closest meeting the leaders of the USA and North Korea have ever had.
Bolton's presence at the meeting risks provoking the North Korean delegation.
In short, the US wants Kim to agree to give up his atomic weapons.
What's more, the official US "memorandum of conversation", or "MemCom", of that meeting was written by the longtime US Russian-to-English interpreter Dmitri Zarechnak, according to a copy of the document posted by the National Security Archive at The George Washington University. The US president turns 72 on Thursday.
Less than a week before the summit, Trump dismissed questions about his readiness, saying, "I don't think I have to prepare very much". Just look at California MORE (D-Calif.), whose office framed it as a rebuttal to one sent last week by top Democrats in the Senate. "That's something that could come out of the meeting".More news: Trump refuses to endorse G-7 communique, threatens Canada with more tariffs
On the other hand, he said, "I am totally prepared to walk away".
Democratic members, however, have their doubts. For whatever reason, he was not listed as a member of the official United States delegation to the Kim Jong Un summit.
"We won't", said Jeffrey Lewis, director of the East Asia program at the James Martin Center for Nonproliferation Studies.
And the day Trump announced he was canceling the summit (just hours before reversing himself to say he was open to having it), a senior White House official said North Korea had promised to let in worldwide observers to watch the purported destruction of a nuclear test site, but had failed to do so.
In a statement obtained by CNN, Rodman says he considers Trump to be a friend and expressed his confidence in his ability to get the job done in their summit.
White House officials have said Rodman will play no official role in the diplomatic negotiations.
Yet Trump and Kim have yet to agree even on how to define denuclearisation of the Korean peninsula - the stated goal of the meeting. Trump and Kim planned to meet one-on-one for most of an hour- joined only by translators.