On the other hand, Sue Mi Terry, who served as a National Security Council aide specializing in Korean affairs under both President George W. Bush and Mr. Obama, said it could yield progress if Mr. Trump proves willing to accept a partial accord short of a comprehensive agreement.
“This meeting could lead to a more substantive meeting down the road, later in the year,” she said in an interview. “I do think Kim could offer just enough on the negotiating table such as the Yongbyun nuclear facility plus yet another suspected nuclear facility in order to secure an interim deal with Trump and at least some sanctions relief.”
Mr. Kim crossed the DMZ in April 2018 to meet with Mr. Moon, becoming the first North Korean leader to step over the line since fighting between the countries ended in 1953. Former Presidents Jimmy Carter and Bill Clinton each visited North Korea, flying into its capital, Pyongyang, but only after they left office. Sitting presidents, including Ronald Reagan, Mr. Clinton, Mr. Bush and Mr. Obama, visited the DMZ, but were never greeted by North Korea’s leader.
Mr. Trump’s meeting with Mr. Kim in Singapore in June 2018 was the first time American and North Korean leaders had met anywhere since the war, and it produced vague promises to pursue an end to Pyongyang’s nuclear arsenal. Their second summit meeting, in Hanoi, ended in failure in February when the two leaders could not agree on a concrete way to accomplish that goal.
North Korean officials went dark after the collapse of the talks, refusing to respond to either the Americans or the South Koreans amid conflicting reports about the fate of the negotiators blamed by Mr. Kim for the failure. North Korea’s missile test was seen as a reflection of Mr. Kim’s frustration over the stalled negotiations.
In recent weeks, however, the North Korean government has re-emerged on the world stage as Mr. Kim exchanged letters with Mr. Trump and met separately with President Vladimir V. Putin of Russia and President Xi Jinping of China in what was seen as a signal of its interest in resuming diplomacy.
American officials have said they did not think a third meeting between Mr. Trump and Mr. Kim should be arranged unless a substantive agreement could be negotiated beforehand to avoid another setback. But Mr. Trump said that since he was already planning to visit the DMZ during his trip to South Korea this weekend, he decided it was worth seeing if Mr. Kim would agree to a short greeting.