As with so many issues involving this president, the views of his aides often have little effect on what he actually says. On Thursday, for example, a senior White House official told reporters that even if the meeting were reinstated, holding it on June 12 would be impossible, given the lack of time and the amount of planning needed.

On Friday, Mr. Trump said, “It could even be the 12th.”

Later on Friday, the president reinforced that possibility, saying on Twitter that if the meeting were rescheduled, it would “likely remain” on that day, “and, if necessary, will be extended beyond that date.”

“We are having very productive talks with North Korea,” he said.

The president brushed off concerns raised privately by his staff and publicly by his allies and adversaries that Mr. Kim was playing him. “Everybody plays games,” he told a reporter. “You know that.”

The White House still has plans to send an advance team to Singapore over the Memorial Day weekend to work out details for a meeting between the two leaders, according to a person briefed on the matter. A similar team waited in Singapore for three days last week, only to be stood up by the North Koreans — a factor cited by officials in judging that North Korea was not serious about the negotiation.

The best strategy now, some argue, would be to hold off on a meeting, tighten the economic vise on the North, and wait for Mr. Kim to come back to the table under more acceptable terms. On Thursday, Mr. Trump appeared to have heeded that advice.

Mr. Bolton, several officials said, is not trying to maneuver against a meeting, in part because he knows it is important to Mr. Trump. But his reference late last month to Libya as a model for the disarmament of North Korea proved extremely destabilizing to the preparations for the meeting.

The North Koreans responded angrily, saying they had no intention of ending up like Libya’s leader, Col. Muammar el-Qaddafi, who gave up his weapons in 2003 and 2004, only to be killed by his own people less than a decade later in a popular uprising that was aided by a NATO-led bombing campaign.