Washington (CNN) President Donald Trump has thrown another twist into the North Korean summit saga, announcing he will meet with leader Kim Jong Un on June 12 after all -- and raising some concern that history may be repeating itself.

Trump met in the Oval Office on Friday with former North Korean spy chief Kim Yong Chol for about 90 minutes -- the highest-level North Korean official to visit the US in 18 years -- and sent him off with a smile and a handshake.

The prospect of a summit instead of the pre-emptive war that many feared just a few months ago drew praise. But, in comments to reporters on the South Lawn afterward, Trump set down markers that seemed to shift the US position in ways analysts said could undermine Washington's leverage.

Trump told reporters he would not add extra sanctions on Pyongyang and would no longer use the term "maximum pressure" -- the international sanctions regimen designed to squeeze North Korea.

'Take your time'

While US officials had said Pyongyang must denuclearize and take action to show it's serious, Trump was vague about North Korea's commitment to do so, even as US intelligence services warn that some of Pyongyang's gestures toward dismantling its weapons programs might be nothing more than propaganda.

And where the administration once talked about a nuclear deal and one summit, Trump on Friday stressed that this is "a process" that will go on for some time: "I told them today, 'Take your time. We can go fast. We can go slowly.' "

For many Korea watchers and national security analysts, it had a familiar ring: a wily North Korean regime parlaying a willingness to talk and the eagerness of its interlocutors into long drawn-out negotiations that give it recognition, concessions and validation.

"Right now, it seems President Trump's North Korea policy is in a state of flux," said Harry Kazianis, director of defense studies at the Center for the National Interest, a foreign policy think tank.

"The Trump strategy now seems to be to cajole the North Koreans into a potential nuclear deal," Kazianis said, by showing Pyongyang that America can guarantee its security and provide massive economic assistance.

"While that may work, my great fear is that North Korea will do what it has always done: Pocket the concessions and economic aid and never give up its nuclear weapons," Kazianis said. "President Trump must be cautious and not fall in the traps that the Kim regime have successfully laid for American presidents for decades."

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Joel Wit, co-founder of 38 North, an authoritative website that tracks North Korea, saw no reason for pessimism.

"My reaction is he's now doing everything he should be doing in the run-up to a summit," Wit said of Trump. "He's toning down his rhetoric, he's emphasizing positive things and he's just on a glide path to what he hopes will be a successful meeting."

Trump emphasized the positive with reporters Friday, even as he discussed sanctions. He said he looked forward to lifting them one day and that wouldn't happen until North Korea denuclearized, but then he softened his rhetoric.

Hundreds of new sanctions that are ready to go will be put on hold, the President said. "Why would I do that when we're talking so nicely?" he added.

"I don't even want to use the term 'maximum pressure' anymore, because I don't want to use that term because we're getting along," Trump said. "You see the relationship. We're getting along."

Not quite maximum pressure

In fact, the US has not been deploying maximum pressure, said Bruce Klingner, a senior fellow at the conservative Heritage Foundation. And in recent weeks North Korea has been building a buffer against US sanctions by cultivating its relationships with South Korea, China and Russia.

Klingner points out that the Trump White House, like previous administrations, has declined to use secondary sanctions to target China for doing business with North Korea.

"Maximum pressure has not been maximum because Trump, like his predecessors, continues to pull punches on enforcing US law," said Klingner.

Another concern is that in publicly announcing he's backing away from the term, Trump is sending a signal that could undermine the international pressure that does exist.

"I think many people are going to feel that not using the phrase 'maximum pressure' signals an end to the sanctions campaign that is premature," said Scott Snyder, director of the program on US-Korea policy at the Council on Foreign Relations. "It means that the North Koreans are getting relief in return for dialogue, when what we need is relief in exchange for action."

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Action is what US officials had been saying they needed to see.

"If we're going to have a summit, they're going to have to make clear what they're willing to do," a senior State Department official, briefing reporters this week, said of the North Koreans. "They have to denuclearize. ... We need action. Yeah, we need a commitment."

But the standards for a summit seemed to have shifted Friday, when Trump was asked whether Kim Jong Un is committed to denuclearizing.

"I think so," the President said. "He'd like to see it happen."

Trump added that Kim "wants to be careful. ... He's not going to run and do things."

It didn't sound like an endorsement of the complete, verifiable and irreversible denuclearization that US officials have been calling for.

"It seems the United States still has not convinced North Korea to abide by CVID," Klingner said.

More theater than reality

Klingner, a former CIA deputy division chief for Korea, pointed out that even as Trump and Kim Jong Un have agreed to meet, the two sides may not be any closer to agreeing on a common interpretation of the term denuclearization.

North Korea, he said, attaches great conditionality to the term. As a self-proclaimed member of the nuclear club, Pyongyang's position has been that it will go to zero nuclear weapons only once all other members of the club do as well -- a nonstarter.

That concerns analysts such as Snyder, who said that "many people were hoping the administration would continue the talks after tangible steps in the direction of denuclearization."

North Korea did make a grand gesture recently, inviting reporters to witness the detonation of underground nuclear test tunnels -- but the US intelligence community now says the performance might have been more theater than reality.

US intelligence and international arms control officials say preliminary analysis of North Korea's detonation indicates the explosions were not strong enough to destroy the tunnels. A US official with knowledge of the findings told CNN that portions of the tunnel complex may remain usable.

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On Tuesday, CNN reported that US intelligence assessments conclude that while Kim could give up some weapons in negotiations with the US -- including warheads and missiles -- he may not be willing to give up the capability to regenerate his program.

On Friday, Trump emphasized that this is just the beginning of a long process.

"June 12th, we'll be in Singapore," he said. "It will be a beginning. I don't say and I've never said it happens in one meeting. You're talking about years of hostility, years of problems, years of, really, hatred between so many different nations."

Trump predicted a "a very positive result in the end."

Analysts and Korea experts say it's too soon to tell. They point to the familiar dance developing between clever North Korean negotiators and US counterparts eager to nail down a deal -- a dance that has ended in failure in the past.

One significant difference this time, Snyder said, is the talks are starting not with low-level negotiators but with Trump himself.

"What we don't know is whether it will be different because we're doing it at the top level," Snyder said.