WASHINGTON (Reuters) - If Donald Trump’s summit next week with North Korean leader Kim Jong Un produces a peace declaration formally ending the Korean War as he has suggested, it could give the U.S. president a big headline-grabbing, made-for-TV moment on the world stage.

FILE PHOTO: A combination photo shows U.S. President Donald Trump and North Korea leader Kim Jong Un in Washignton, DC, U.S. May 17, 2018 and in Panmunjom, South Korea, April 27, 2018 respectively. REUTERS/Kevin Lamarque and Korea Summit Press Pool/File Photos

But the public relations value of such a historic event could quickly fade if Trump fails, in return, to wring any significant concessions from Kim toward the dismantling of his nuclear arsenal, former U.S. officials and analysts say.

After meeting a top North Korean envoy on Friday, Trump appeared suddenly to back away from his demand for Pyongyang’s swift, complete denuclearization. He suggested instead that the most tangible outcome of the unprecedented June 12 summit in Singapore could be the “signing of a document” to bring the technical state of hostilities to a close - 65 years after the Korean conflict ended with an armistice, not a peace treaty.

While Trump might seize on that as a way to tout the summit as a foreign policy success, it would mean granting North Korea something it has sought for decades but which previous administrations have said would only be possible if Pyongyang first agreed to give up its nuclear weapons.

Any end-of-war declaration - even if short of an actual treaty - could erode U.S. leverage in future negotiations if North Korea does not give ground on nuclear issues, experts warned. It also could give Pyongyang a stronger platform to press for a halt to joint U.S.-South Korea military drills, as well as the removal of U.S. forces from the South.

There are even some doubts within the administration on the wisdom of such a move, especially since it may do nothing to stop North Korea’s development of nuclear missiles it says are capable of hitting the United States.

“A peace treaty would be a major accomplishment,” said one U.S. official involved in summit preparations. “But whether it would also be the start of eliminating the dangers North Korea poses to its neighbors with its weapons programs and to others with its exports of weapons and technology is far from certain.”

Evans Revere, a former U.S. negotiator with North Korea, said any kind of joint peace declaration at this stage – when Pyongyang has shown no real willingness to give up its nuclear program – would be premature.

“Among the many traps that the U.S. president might fall into in Singapore, this would be a powerfully significant one,” he said.

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But Trump’s aides say a peace agreement early on could lower tensions, clear the air for future nuclear talks and undercut North Korea’s longtime contention it needs its nuclear program to deter a “hostile” United States. Washington keeps 28,500 troops in South Korea, a legacy of the 1950-53 war.

The White House did not respond to a request for comment.

‘CAN YOU BELIEVE ...?’

Trump’s effort might appear a worthy goal and in line with South Korean President Moon Jae-in’s recent agreement with Kim to seek an end to the conflict between the Koreas. There has been media speculation that Moon might travel to Singapore for the summit, although South Korean officials stress they are considering a three-way meeting at a later date.

The idea of a peace deal may also appeal to Trump, a former reality-TV star, because it would allow him to claim an achievement no other president has had. At the same time, it might boost supporters’ hopes he could win a Nobel Peace Prize.

“Can you believe that we’re talking about the ending of the Korean War?” Trump mused to reporters on Friday, saying it would be a “historically” important moment.

But the reason previous administrations have not offered such an agreement – or even to hold a summit between the countries’ leaders that North Korea has long sought – is that Pyongyang has resisted nuclear disarmament.

U.S. officials have welcomed Kim’s recent announcement of a suspension of long-range missile tests and the closing of his nuclear bomb test site but say these steps are reversible.

Trump has left unclear whether he seeks the possible signing of an actual peace treaty, which experts believe would require lengthier negotiations, or a political statement agreed upon by the two sides that could form the basis of a detailed accord.

Upgrading the armistice to a full-scale treaty also would likely require all signatories, which includes China, allied with North Korea during the war, in addition to Pyongyang and Washington, which headed the United Nations command.

China’s Foreign Ministry said it supports efforts to reach a “peace mechanism.” But the influential state-run Global Times newspaper said Beijing must be a signatory to any peace treaty “to ensure its legal and historical status.”

Either way, it could have major implications and possibly unintended consequences for the United States.

“Kim would like nothing better than to drag the U.S. into prolonged negotiations over America’s military presence in the South,” said Danny Russel, a former top Asia policy adviser in the Obama administration.

“But what the North Koreans are more likely to have in mind for Singapore is a quick win via a vague declaration that the two leaders commit to preserving peace and to reaching a permanent peace arrangement,” he said.