North Korean leader Kim Jong Un, right, and South Korean President Moon Jae-in walk together at the border village of Panmunjom in the Demilitarized Zone, South Korea, Friday, April 27, 2018. (Korea Summit Press Pool via AP)

Friday was quite a busy day in Panmunjom in the Korean peninsula’s demilitarized zone. At the first high-level summit between North and South Korea in over a decade, President Moon Jae-in and supreme leader Kim Jong Un agreed on three major points: 1) to improve inter-Korean relations with the ultimate goal of reunification, 2) to reduce tensions and eliminate the danger of war, and 3) to establish a robust peace regime.

Despite skepticism that Kim would reaffirm his commitments at home, both sides widely circulated the “Panmunjom Declaration.” The document’s substance is not much different from agreements that have come before (in 1992, 2000 and 2007) and ultimately failed.

Expectations in Korea are running high, though. This declaration’s language is plainer, some parts are already being implemented and the domestic and international circumstances — not to mention the key players’ personalities — are strikingly different in 2018.

The agenda is massively ambitious and risky, like scaling Everest — or perhaps in this case, Mount Paektu, which Moon hopes to climb during his visit north of the DMZ this fall. Here are four things to remember as the two leaders attempt to conquer this particular mountain:

1) It’s called a summit, but it’s actually base camp

Moon and Kim have agreed to a destination, a substantial achievement, but the route ahead remains uncharted. Progress between the two Koreas is the most important factor determining lasting peace on the peninsula.

Yet other countries are necessarily involved, including China, Japan and the United States. President Trump is pleased so far, but continued movement toward mutually beneficial outcomes relies significantly on outsiders’ steadfast support and engagement.

At this stage, it is less useful to assign “credit” or “wins” to Moon, Kim or Trump. Each is staking his reputation and political survival, at least in part, on getting something out of the meetings yet to come.

Insofar as the United States and China helped create the stalemate (e.g., denuclearization as a precondition for talks — or lax sanctions enforcement) and have their own set of priorities, their involvement may well sober the current euphoria.

The absence of Japan and Russia to date may complicate matters as well. Prime Minister Shinzo Abe is actively working to become more involved and Moscow may be cozier with Pyongyang than Beijing has been. Greater numbers will make cooperation more difficult.

2) The danger of altitude sickness is real

The attitude shifts among the key players have come at a dizzying pace over the past six months. On Nov. 28, North Korea concluded a long series of provocative nuclear and missile tests. In December, the South’s Yonhap news agency confirmed a “decapitation unit” could assassinate Kim in case of war. In January, Trump was comparing nuclear buttons with Kim, peppering his public appearances with insults and threats.

But by February, the Koreas symbolically united for the Pyeonchang Olympics. Kim then agreed to the Moon and Trump summits in early March. The abrupt turnabout means that some security experts still place high odds of the chance of war. Some analysts believe that the Trump administration’s approach betrays a lack of sincerity — or that any diplomacy failure might become a pretext for preventive strikes or regime change.

It’s useful to recall that diplomatic relations between the United States and China were not fully cemented when President Nixon first traveled there in 1972. Normalization came several years later in 1979, after a long process.

3) It would be an easier climb with the right equipment in place

In the years since the last inter-Korean summit, human and diplomatic contact between the two countries virtually ceased. Without regular interactions, civilians on both sides increasingly viewed one another with mutual fear and suspicion. A recent Asian Institute poll found that nearly half of South Koreans in their 20s describe Northerners as “enemies” or “strangers.”

Equally important, routine intergovernmental relations simply don’t exist. When diplomatic ties and communications between countries are limited, small problems take on outsized importance and can create unnecessary misunderstandings.

There’s some progress already on a neutral framework for cross-border engagement. The two sides agreed last month to establish a security hotline and additional lower-level meetings are occurring. And there’s discussion of an August reunion for families divided by the DMZ since the 1950s.

Building up the U.S. capacity to engage in this new era of Korean diplomacy could also take some time. Appointing a U.S. ambassador to South Korea would be a first step to help the United States to effectively pursue its interests — along with perhaps creating new positions to handle the critical months and years ahead. Laying the groundwork for U.S. diplomacy also might assuage concerns in Asia that the United States is an unreliable partner.

4) Both sides may face a rocky path

As arms control expert Jeffrey Lewis has written, the two sides may well have different end games in mind for denuclearization on the Korean peninsula. Or the United States may not be willing or able to offer the security guarantees sufficient to convince Kim to CVID — complete verifiable irreversible dismantlement — of his nuclear weapons. Many in both Koreas may be concerned that Trump will be fickle, supporting talks today, but responding to setbacks with a quick resort to force.

But foreign policy experts point out that the use of force, even limited force, will generate large costs on the Korean peninsula. As Tanisha Fazal argued here at the Monkey Cage, casualties also would be high for U.S. troops in the region.

Many analysts also note that there are no good options, but continued dialogue on North Korea’s weapons program is the least bad choice. Mark Bell noted here in the Monkey Cage that talks can produce other gains — fewer nuclear reactors and tests, perhaps, and better intelligence about North Korea and its weapons facilities. Denuclearization is a goal, but it is not the only one.

Seoul and Washington have reason to be cautious in their pursuit of peace with Pyongyang. The steps taken so far are significant, but it is all uphill from here.

Bridget L. Coggins is associate professor of political science at the University of California, Santa Barbara and an adjunct fellow with the CSIS Korea Chair in Washington, D.C. Follow her on Twitter @BridgetCoggins.