Kim, Trump to try to narrow differences

Analysts believe that differences over the definition of denuclearization - and necessary compromises to be made on both sides - will be critical for ultimate success.

Trump earlier had demanded swift denuclearization of the DPRK, but he has recently kept saying it is going to be a process that will take time.

The DPRK has long argued that its nuclear weapons program is for self-defense.

The ROK President Moon Jae-in expressed hope on Monday for the success of the summit, but said it will only mark the start of a "long process" of denuclearizing the DPRK, which he said could take years, the ROK's Yonhap News Agency reported.

Trump called both Moon and Japanese Prime Minister Shinzo Abe on Monday.

"Trump has adopted a more restrained and cooperative attitude, but it remains highly uncertain what substantive concessions he will be willing to make," said Ted Carpenter, a senior fellow for defense and foreign policy studies at the Cato Institute, a Washington-based think tank.

People surrounding Trump, such as Pompeo, national security adviser John Bolton and Vice-President Mike Pence, have opposed concessions on the US side.

Ruan Zongze, vice president of the China Institute of International Studies, said both Pyongyang and Washington need this meeting. Trump needs a miracle to break the quandary he faces at home, and breaking the ice with Pyongyang is worth trying, Ruan said. Kim needs to cement his leadership and foster a favorable external environment by improving relations with the US.

Chen Gang, a senior research fellow with the East Asian Institute at the National University of Singapore, said the fact that the summit is being held demonstrates that both the DPRK and the US agree to resolve the issues by dialogue. However, Chen added, due to the long-standing confrontation, the two sides still have differences in many aspects. So it is still important that they keep the peaceful momentum of recent progress and strive for the political settlement of the peninsula issues.

Carpenter expressed that there is still a decent chance that Washington would agree to a peace treaty formally ending the Korean War (1950-1953) and a reduction in the number of military exercises with the ROK.

But he said there is very little chance of a troop withdrawal or a rapid lifting of sanctions.

Carpenter said he thinks the key issues are whether Trump will consider diplomatic recognition of the DPRK and at least a phased lifting of sanctions. "Without those concessions, an agreement is unlikely," he said.

"The entire East Asian region has reasons to breathe with a sense of relief over the Kim-Trump meetup in Singapore," said Zha Daojiong, a professor at the School of International Studies of Peking University.

But he said it is hard to predict what may come out of the meeting, as the change in tone between the two leaders was very abrupt.

"So long as the two sides keep talking, even at lower levels, there is a chance for peace, or peace of mind," Zha said.