Negotiations with North Korea are showing promising signs of success — just not the negotiations involving the Trump administration.

For all the fanfare of President Donald Trump's historic summit with North Korean leader Kim Jong Un in Singapore in July, the denuclearization agreement they signed was vague to the point of being effectively meaningless, according to many experts.

That lack of clarity appears to have slowed the ensuing talks between Washington and Pyongyang to a halt, with neither side able to agree on how to progress.

NBC News reported this weekend that his administration is taking an increasingly aggressive stance because of evidence North Korea is still making nuclear weapons, according to senior U.S. officials.

Kim did offer a potential olive branch to Trump last week, and the two sides say they're planning a second summit. It's unclear if these moves will be enough to break the deadlock.

And yet in the background, often drowned out by the din of Trump's headline-grabbing promises, a second, quieter set of negotiations between North and South Korea has been far more encouraging.

"There are currently two parallel diplomatic tracks in play: the peace track driven by Seoul and the denuclearization track driven by Washington," according to Abraham Denmark, a director at the Woodrow Wilson International Center for Scholars.

"The peace track has made much more progress so far," he said.

A puzzle

The two Koreas, divided by a war in the 1950s that technically has never ended, have recently traded apocalyptic threats, deadly shell fire and even propaganda music blasted over the border by hulking loudspeakers. As recently as last September, Pyongyang warned it could wipe out the South in a nuclear strike.

But things began to change after the election last year of Moon Jae-in, a liberal human-rights lawyer, as South Korea's president.

South Korea's President Moon Jae-in with North Korean leader Kim Jong Un during their second summit on May 26. KCNS / AFP - Getty Images

Moon has been "a key driver of this diplomacy since its inception," Denmark said, because he's proved to be a skilled and effective navigator among Kim, Trump, China and Japan.

Moon suggested that Trump should be nominated for the Nobel Peace Prize for his overtures to North Korea. Some who watch these talks closely say, if anyone is nominated, it should be Moon.

Since Moon came to power, there have been big symbolic gestures. The Koreas fielded a united hockey team at the Winter Olympics in PyeongChang, South Korea, in February, and there was the historic meeting between Moon and Kim at the Demilitarized Zone months later.

The symbols also had some substance behind them. At their first summit, in April, Moon and Kim signed a detailed agreement called the Panmunjom Declaration in which they pledged to work toward ending the Korean War and avoid military provocations. It also allowed families divided by the war brief and emotional reunions, and held the promise of future economic ties.

This weekend, a military parade in Pyongyang marking 70 years since the country's foundation eschewed the usual display of long-range missiles for a float celebrating the declarations signed with the South.

The celebration also involved a vast gymnastic display involving 100,000 performers. Here, traditional songs praised Korean shared culture, and imagery focused on joining hands after seven decades of separation.

The showpiece involved thousands in the stadium holding up white cards that formed one giant screen. Onto this was beamed highlights of Kim and Moon's summit. The crowd erupted in applause, as did Kim who was in the audience.

The Panmunjom Declaration symbolized the different approaches taken by South Korea and the U.S. The declaration pledges to work toward denuclearization, but many analysts believe Moon sees a nuclear-free Korea as an eventual goal that might be achieved through step-by-step concessions.

On Tuesday, Moon said Trump and Kim needed to make "make bold decisions," and urged the U.S. to "take a corresponding step" if the North is to denuclearize.