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For the United States, talks with North Korea are focused on the very clear aim of denuclearization. However, the North Korean side wants a trade-off: a formal end to the Korean War. And it isn’t just North Korea pushing that idea.

Following a historic three-day summit with North Korean leader Kim Jong Un in Pyongyang this week, South Korean President Moon Jae-in told reporters that both Koreas hope the status of the Korean War is resolved by the end of the year.

Moon, who is expected to meet with President Trump in New York at the United Nations General Assembly next week, said he would discuss with him the goal of declaring an end to the war. Moon also said that Kim wants a new summit with Trump to speed up the denuclearization process.

So far, the U.S. government has resisted the idea of formally declaring an end to the war without visible progress toward North Korea’s nuclear disarmament. Many in Washington worry that such a declaration could undermine the justification for keeping U.S. troops in South Korea and weaken the U.S. alliance with Seoul.

But Moon’s remarks served as a reminder that the future of the two Koreas is still tightly tied to their past — in particular, to a war in which the bulk of the fighting stopped 65 years ago.

Why the Korean War didn’t end

Although the war lasted from 1950 until an armistice in 1953, the last two of those years were pretty much a deadlock. The end result was, in many ways, inconclusive.

During the first months of the war, the North invaded the South and stormed nearly all the way down the Korean Peninsula. Then a counterattack by United Nations troops brought the U.S.-led forces to the North’s border with China. Finally, an invasion by China pushed the U.N. forces back to the area around the 38th parallel, where the front lines would remain.

Even if little territory was exchanged, the rest of the war was devastating. North Korea was subjected to a huge bombing campaign, and estimates suggest that 2.5 million civilians died during the conflict. For years, there was talk of an armistice agreement to end the fighting, but a number of issues, including the repatriation of prisoners of war, kept that from happening.

The election of Dwight D. Eisenhower as president in 1952 and the death of Soviet leader Joseph Stalin helped spur negotiations, and North Korean and Chinese forces and the U.N. Command finally signed an armistice on July 27, 1953. The agreement halted fighting and established the demilitarized zone (DMZ). South Korea was not a party to the armistice; indeed, South Korean President Syngman Rhee had wanted to keep fighting.

In theory, the armistice was meant to be temporary, calling for a "complete cessation of hostilities and of all acts of armed force in Korea until a final peaceful settlement is achieved.” But a peace conference held in Geneva in 1954 failed to find a full peace deal, in large part because both sides considered themselves the victors. Escalating tensions in what was then French Indochina also complicated matters. The United States subsequently abrogated one part of the armistice by moving nuclear weapons into South Korea in 1958. (They were eventually removed in 1991.)

Though full-fledged fighting never resumed, military tensions remained high. There have been a number of violent incidents, including in 1976 when North Korean soldiers hacked two U.S. Army officers to death in the DMZ after the Americans tried to trim a tree. Since the 1990s, North Korea has frequently said it would no longer abide by the armistice.

North Korean leader Kim Jong Un, left, shakes hands with South Korean President Moon Jae-in on April 27 at the truce village of Panmunjom. (Korea summit press pool/AFP) (KOREA SUMMIT PRESS POOL/AFP/Getty Images)

What is the current situation?

When North Korea’s Kim met South Korean President Moon at the Panmunjom truce village in the DMZ in April, the two men agreed to work toward “declaring an end to the war and establishing a permanent and solid peace regime.”

For North Korea, the appeal of the end of the Korean War is obvious: It would help legitimize the North Korean regime — perhaps even leading to diplomatic recognition from the United States — and add another small barrier to renewed conflict on the peninsula.

Some experts have suggested that the process could start with a U.S.-North Korea declaration that the Korean War has ended ― a move that would carry big symbolic weight but require fewer legal hurdles than turning the armistice agreement into a full peace treaty. That would potentially require coordination with Beijing as well as the approval of Congress.

South Korea sees a declaration as a way to improve inter-Korean relations and pave the way for a peace treaty. But because Seoul is not a party to the armistice, its views carry less legal weight. And though Beijing has signaled its willingness for a peace treaty or declaration, the messages from Washington have been mixed.

What role does the United States play?

Trump has shown public enthusiasm for the idea of a permanent peace, tweeting “KOREAN WAR TO END!" in April. And according to a report from Vox, when Trump met with Kim in Singapore on June 12 for a historic U.S.-North Korea summit, he privately said he would sign a declaration to end the Korean War soon after their meeting.

But while the agreement signed in Singapore by Trump and Kim contained a reference to building a “lasting and stable peace regime on the Korean Peninsula," the United States has indicated it sees this as something that would happen only after North Korea agrees to give up its nuclear weapons.

“Look, we support a peace regime, a peace mechanism by which countries can move forward toward peace,” State Department spokeswoman Heather Nauert said Tuesday. “But … our main focus is on the denuclearization of the Korean Peninsula, and that’s something we’ve been very clear with many governments about.”

This difference in aims has put the two sides at loggerheads. North Korean state media has criticized the U.S. negotiating stance, which puts the emphasis on nuclear weapons.

“Let us adopt the declaration on ending war, build a peace mechanism to make durable peace,” the North’s state-run Korean Central News Agency wrote last month. “Let us not insist on ‘denuclearization first’ only and never pardon the unreasonable act of the U.S. forcing the north to make a unilateral concession!”

The U.S. government is wary of rushing into a declaration of the end of the Korean War for much the same reason that North Korea wants it. Even though such a declaration may not carry significant legal weight, it would serve as a symbolic recognition of North Korea as a nuclear state and strengthen calls to downsize the U.S. military presence in South Korea.

Any declaration could also be seen domestically as a capitulation by Trump, marring what his administration has portrayed as a clear victory for his “maximum pressure” approach. If the declaration were too weak, North Korea could reject it out of worries that it could be overturned by a subsequent government; if it were too strong, the United States would have given up one of its strongest cards too early in negotiations.

But with progress slow on the denuclearization front more than three months after Trump met with Kim, the United States may be forced to consider methods of speeding it up.

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