IT WAS easy to forget that this was a man who has threatened the world with nuclear war, used summary executions and foreign hit jobs to eliminate his rivals and presided over some of the worst human-rights abuses in recent history. Kim Jong Un, the leader of North Korea, was all smiles as he walked towards the line that separates the northern and southern halves of the demilitarised zone dividing the two Koreas on the morning of April 27th. Mr Kim literally stretched a hand across the frontier, shaking that of Moon Jae-in, the South’s president, before stepping into the South. In a winningly unscripted move, he persuaded Mr Moon to re-cross the line into the North with him, before heading south again.

The meeting marked the first time a North Korean leader has travelled to the South since the end of the Korean war in 1953. (South Korean presidents have twice visited Pyongyang for summits, in 2000 and 2007.) There were Kodak moments galore: the first handshake, an inspection of a South Korean honour guard dressed in an assortment of primary-coloured nineteenth-century uniforms, the planting of a “peace tree”, a private afternoon chat on a bench, during which observers could see the two leaders but hear only birdsong.

The continuous display of bonhomie meant that the two leaders achieved their first objective: to show that their countries could set aside their traditional enmity to conduct a good-natured conversation. In South Korea, the moment prompted an outpouring of emotion. Social media exploded with amazed comments. Commuters stopped in subway stations to watch it on live TV. Children were given time off school to do the same. Even hardened hacks whooped and applauded as the two leaders shook hands. Some fought back tears.

The initial encounter set the mood for the rest of the day. Mr Kim displayed a warmth that was notably at odds with his record of threats and provocations. During a moment of playful banter before the doors closed on the press, the dictator joked about the difficulty of bringing North Korean noodles with him for the evening banquet and complimented Mr Moon on the high quality of the South’s roads.

This charm offensive certainly resonated with South Koreans. The noodles to which Mr Kim referred began trending on social media and became a lunchtime hit in many of Seoul’s restaurants. On the streets of Goyang, a suburb north of Seoul, the mood was jubilant. “I used to call President Moon a filthy commie but I don’t really know why anymore,” said Mrs Kim (presumably, no relation), a middle-aged resident. “He’s clearly doing great things—and he’s even quite good-looking!”

For all the pomp and skilful choreography, however, the results of the summit were insubstantial. The joint statement the two leaders signed before sharing a hug and a banquet of symbolic dishes was full of lofty sentiments, but short on detail: “The two leaders solemnly declared before the 80m Korean people and the whole world that there will be no more war on the Korean peninsula.” They also expressed a desire to bring about a formal end to the Korean war by the end of this year, by transforming the existing armistice into a peace treaty with the help of America and China. And after rushing to perfect a nuclear bomb, and celebrating volubly at each successful test, Mr Kim declared that in fact he wanted a “nuclear-free Korean peninsula”.

The declaration signed at the previous inter-Korean summit, in 2007, contained similar language on the nuclear issue. Needless to say, it has not been fulfilled. Mr Kim’s father and predecessor, Kim Jong Il, had a habit of cheating on nuclear commitments before the ink was dry. And both Kims saw nuclear weapons as essential to the survival of their regime, and their regime’s survival as essential to their own.

The wording of the new statement does not preclude Northern demands that might derail talks again, such as an insistence that all American troops be withdrawn from the South. Mr Moon has claimed that Mr Kim is willing to drop that idea, but if so, there was no sign of it in the declaration. Indeed, there were no tangible concessions from the North (or, for that matter, the South).

Still, there was never any chance that a deal on nuclear disarmament would be agreed without American input. The administration of Donald Trump welcomed the outcome of the summit; the president himself tweeted “KOREAN WAR TO END! The United States, and all of its GREAT people, should be very proud of what is now taking place in Korea!” The warmth of the proceedings, and Mr Trump’s even warmer response to it, suggests that his mooted summit with Mr Kim, which is supposed to take place in late May or early June, will indeed go ahead. But what the outcome of that meeting will be, or even what the two sides will offer, remains as opaque as ever. And next time around, the measure of success will be more than warm smiles and shiny photographs.