Bill Clinton has been famously successful in North Korea and on a mission that the West considers to be one of the best kept secrets of international diplomacy. The triumph is as personal as it is of the US.

The former president has secured the release of two American journalists, Laura Ling and Euna Lee, who had been arrested by Pyongyang in March for having strayed into the country from China while on an assignment. Beyond their freedom, Mr Clinton has choreographed a watershed development in the US’s historically strained relations with North Korea.

As recently as June, Ling and Lee had been sentenced to 12 years’ hard labour. They have now been granted a ‘special pardon’, an incredibly dramatic turnaround by the North Korean authorities almost immediately after Clinton’s meeting with the ailing ruler, Kim Jong-il. Whether the former US President had delivered to Kim a verbal message from Barack Obama must remain a subject of conjecture. Just as it can merely be speculated upon whether the two journalists’ road to freedom was paved by Hillary Clinton’s appeal for amnesty, or by a nudge and a nod from China.

Implicit in Mrs Clinton’s appeal was an indication that Ling and Lee had violated the laws of North Korea. The world may never know whether Mr Clinton’s achievement was preceded by a flurry of diplomatic activity. For, it is not often that Mr Kim grants audience to a visiting dignitary within hours of his landing.

Beyond the two individuals’ march to freedom lies the almost intractable irritant. The development has simultaneously raised hopes that Mr Clinton’s meeting with North Korea’s ‘Dear Leader’ could eventually break the ice, ending Pyongyang’s nuclear standoff with the US. It has been a momentous forward movement since the Bush dispensation branded the North as being part of the ‘Axis of Evil’. For all that, the fact remains that the defiant testing of a nuclear device and long-range missiles together pose a daunting challenge to President Obama’s foreign policy. International relations will truly be on the turn if Mr Clinton’s mission of mercy can in the fullness of time lead to developments of still greater moment... to the benefit of both countries. The real test concerning matters nuclear will be keenly watched by the comity of nations.