Kim Jong Un walks south to meet his rival: Can they deal?

GOYANG, South Korea -- There will be plenty to gawk at today when North Korean leader Kim Jong Un walks south across the world's most heavily armed border and stands face-to-face with South Korean President Moon Jae-in. Two men who seemed on the verge of war months ago will take a pleasant walk, plant a commemorative tree, inspect an honor guard and belly-up to a lavish banquet.

What's less clear is whether the rivals can make any progress on the only thing the world really cares about: North Korea's growing arsenal of nuclear weapons.

The North likely has work to do before it perfects the finer technological points on its long-range nukes, but there's little question it stands on the threshold of becoming what Kim says his nation already is: A nuclear weapons power.

Today's summit will be the clearest sign yet of whether it's possible to peacefully negotiate those weapons away from a country that has spent decades doggedly building its bombs despite crippling sanctions and near-constant international opprobrium.

Expectations are generally low, given past so-called breakthroughs on North Korea's weapons have collapsed amid acrimonious charges of cheating and bad faith. Skeptics of engagement have long said the North often turns to interminable rounds of diplomacy meant to ease the pain of sanctions, give it time to perfect its weapons and win aid for unfulfilled nuclear promises.

Advocates of engagement say the only way to get a deal is to do what the Koreas will try today: Sit down and see what's possible.

Moon, a liberal whose election last year ended a decade of conservative rule in Seoul, will be looking to make some headway on the North's nuclear bombs in advance of a planned summit in several weeks between Kim and President Donald Trump. Kim, the third member of his family to rule his nation with absolute power, is eager, both in this meeting and in the Trump talks, to talk about the nearly 30,000 heavily armed U.S. troops stationed in South Korea and the lack of a formal peace treaty ending the Korea War -- two factors, the North says, making nuclear weapons necessary.

North Korea may also be looking to use whatever happens in the talks with Moon to set up the Trump summit, which it may see as a way to legitimize its declared status as a nuclear power.

One possible outcome today, aside from a rise in general goodwill between the countries, could be a proposal for a North Korean freeze of its weapons ahead of later denuclearization. Seoul and Washington will be pushing for any freeze to be accompanied by rigorous and unfettered outside inspections of the North's nuclear facilities, since past deals have crumbled because of North Korea's unwillingness to open up to snooping foreigners.

South Korea, in announcing Thursday some details of the leaders' meeting, acknowledged the most difficult sticking point between the Koreas has been North Korea's level of denuclearization commitment. Kim has reportedly said he wouldn't need nuclear weapons if his government's security could be guaranteed and external threats were removed.

Whatever the Koreas announce Friday, the spectacle of Kim being feted on South Korean soil will be something to behold. Kim and Moon will be enjoying each other's company in the jointly controlled village of Panmunjom near the spot where a defecting North Korean soldier recently fled south in a hail of bullets fired by his former comrades.