Leading article: A former President who still knows how to play his part

Mission accomplished, Bill Clinton has left the ball in North Korea's court

Two young Americans rescued from 12 years of penal servitude behind one of the world's last iron curtains – the emotional scenes at Burbank airport seemed to say it all. The women emerged from the plane tearful, but overjoyed. Their families were at the foot of the steps to meet them. So was their employer, Vice-President turned media-owner, Al Gore. There was much kissing, hugging and crying, and a heartstrings-tugging speech from Laura Ling. It was a classic piece of all-American theatre, and none the worse for that.

But those scenes in the airport hangar did not say it all, nothing like. Behind the freedom of Ms Ling and her colleague, Euna Lee, lay one of the most ingenious and ambitious diplomatic ventures seen for many years. The extent of its success will become clear only in the coming weeks, perhaps months, even years. The pardon granted to the two journalists, who had "confessed" to crossing illegally into North Korea, was an immediate reward for this bold approach. With its success, new prospects have opened up.

Former US presidents have a notable track record as extraordinary envoys, Jimmy Carter being a distinguished example. But Bill Clinton wields particular political and personal authority. Not only is he the most recent former Democratic US President, and so the direct forerunner of Barack Obama, but he left office in a blaze of international goodwill, leaving two major initiatives – on the Middle East and, as it happened, on North Korea – incomplete. The other reason for his special position is that his wife is US Secretary of State.

Mr Clinton was the consummate insider-outsider to undertake this ultra-sensitive mission. The White House could, as it did, deny any direct part in the undertaking, while the North Korean leader, Kim Jong-il could, as he did, bask in the reflected glory of this global superstar paying court. The public choreography of the meetings in Pyongyang was at least as significant as that in the Los Angeles airport hangar, where Mr Clinton contented himself with genial restraint and left the speaking to Ms Ling and Mr Gore.

In the North Korean capital, Mr Clinton adopted the formality and the grave public mien of his host. The message was that this was serious; business not pleasure. Kim Jong-il, it can safely be assumed, does not do public cordiality. He needed pictures that showed a meeting of equals. But nor could Mr Clinton be seen to be looking too cheerful with a leader who is at loggerheads not just with the US, but much of the rest of the world as well. He played the part to perfection.

The other key to this meeting came in Mr Gore's short speech, where he carefully described the mission as "humanitarian". Again, this official description suited both sides. It restricted the US objective to the plight of two young women journalists and allowed North Korea's leader to appear magnanimous and in control, with no further obligations to be met. The composition of Mr Clinton's delegation, however, which included his long-standing chief of staff and a former State Department Korea expert, suggests something more, perhaps much more, was afoot.

The White House and State Department both denied that Mr Clinton had taken with him any personal message, whether on Pyongyang's nuclear programme or anything else. In truth, though, he did not need to. He was the message – a message that the door to engagement is not closed. If it is recognition that North Korea craves, Mr Clinton will surely have left its leader in no doubt about what he must do next.