“What is nagging at me is that these alleged promises or concessions from Kim Jong-un seem so out of character for North Korea’s 34-year-old leader,” Jung H. Pak, a former C.I.A. analyst who is now a senior fellow at the Brookings Institution’s Center for East Asia Policy Studies, said in an essay posted on the Brookings website.
Even if the South Koreans faithfully relayed Mr. Kim’s offer, the muddled aftermath of Mr. Trump’s surprise announcement illustrates how little control he has over the momentum behind the diplomatic opening. The leaders of North and South Korea are scheduled to meet at the end of April, setting the stage for the Trump-Kim summit meeting a month later.
“The president, and now Pompeo with him, are flowing into an initiative that has been driven by the Koreans,” said Philip D. Zelikow, who served in the State Department during the George W. Bush administration. “A lot of the key spadework on this is going to unfold before Pompeo is on the job.”
Mr. Zelikow, who has been involved in back-channel negotiations with North Korean representatives over the years, said that they have seized the strategic initiative for the meeting, which would give them an advantage in setting the time, place and agenda for the encounter.
“They are trying to delay and defuse the danger of a war,” Mr. Zelikow said. “The best-case scenario is that there would be some agreement on principles that would guide future negotiations.”
Mr. Trump’s national security adviser, Lt. Gen. H. R. McMaster, traveled to New York on Monday to brief members of the United Nations Security Council about the president’s decision to meet with Mr. Kim. General McMaster said the invitation vindicated the president’s strategy of imposing “maximum pressure” on the North.
But he also counseled caution, according to a person who heard him speak, laying out the possible hurdles and reaffirming that the sanctions needed to be kept in place. Matthew Pottinger, the National Security Council’s senior director for Asia, offered the diplomats a litany of reasons previous negotiations with North Korea had failed.
Two obvious candidates to consult on talks are no longer available to the White House: Joseph Y. Yun, a Korean-born American diplomat who negotiated with Pyongyang for the return of a detained American, Otto F. Warmbier, resigned from the Foreign Service. Victor D. Cha, a Korea expert in the Bush administration, was on track to be ambassador to Seoul before the White House pulled the plug on his nomination.
Even inside the White House, some officials express regret that Mr. Cha was blocked. Among those now under consideration for the post, according to a person briefed by the White House, are two retired generals who commanded troops in South Korea: Walter L. Sharp and James D. Thurman.
With no ambassador in place and the State Department in flux, Mr. Pottinger and his staff are handling much of the preparations for the meeting. But the National Security Council is itself on edge, amid persistent rumors that General McMaster might soon depart.
Even in a hawkish administration, Mr. Pompeo’s statements about North Korea have been hard-line. Last summer, speaking at the Aspen Security Forum, he came as close as any official in calling for the removal of Mr. Kim.
“The thing that is the most dangerous about it is the character who holds the control over” North Korea’s nuclear arsenal, Mr. Pompeo said.
“From the administration’s perspective, the most important thing we can do is separate those two. Right?” he continued. “Separate capacity and someone who might well have intent, and break those two apart.”
Mr. Pompeo’s C.I.A. background could help him assess the authenticity of the North Korean offer. But with no diplomatic experience, he will not be able to offer Mr. Trump much advice on how to handle Mr. Kim or how to approach a complex negotiation.
Given all those limitations, said Jeffrey A. Bader, a former Asia adviser to President Barack Obama, Mr. Trump should consider appointing a special negotiator to take charge after his initial meeting with Mr. Kim.
“They got two months to pull this together,” Mr. Bader said. “They don’t have language from the horse’s mouth on North Korea’s offer, don’t have clarity on a plausible U.S. objective, don’t have a venue, don’t have a date — and they’ve got no experienced negotiator.”