Imagine that five American nurses and a British doctor have been detained and tortured in a Libyan prison since 1999, and that a Libyan prosecutor called at the end of August for their execution by firing squad on trumped-up charges of deliberately contaminating more than 400 children with HIV in 1998. Meanwhile, the international community and its leaders sit by, spectators of a farce of a trial, leaving a handful of dedicated volunteer humanitarian lawyers and scientists to try to secure their release.

Implausible? That scenario, with the medics enduring prison conditions reminiscent of the film Midnight Express, is currently playing out in a Tripoli court, except that the nationalities of the medics are different. The nurses are from Bulgaria and the doctor is Palestinian (see page 254).

Despite the medics' plight, the United States agreed in May to re-establish diplomatic relations with Libya, 18 years after the bombing of an airliner over Lockerbie in Scotland that killed 270 civilians. Many observers had expected a resolution of the medics' case to be part of the deal. And the European Union has given Muammar Gaddafi, the Libyan leader, red-carpet treatment at the European Commission in Brussels.

International diplomacy, dealing as it does with geopolitical and economic realpolitik, by necessity often involves turning a blind eye. But its lack of progress in response to the medics' case in Libya is an affront to the basic democratic principles that the United States and the European Union espouse. Diplomacy has lamentably failed to deliver.

The principles of law and science have the common aim of discovering the truth. A previous assessment of the case by two prominent AIDS researchers, Luc Montagnier and Vittorio Colizzi, concluded that the charges are false, that the medics are innocent, and that the infections resulted from poor hygiene in Libya's hospitals. It was not a plot orchestrated by the CIA and Israel's Mossad, as President Gaddafi alleged in 2001 — an allegation that has driven a popular thirst for vengeance in Libya.

The case is politically embarrassing for Gaddafi. Finding a scapegoat is easier than having to admit that the infection of the children was an accidental tragedy. But the most likely diplomatic compromise — that the medics will be condemned to death, with this being commuted to a life sentence — is unacceptable. They are innocent, and the law and science can prove it, if they get the belated opportunity.

That is why scientists should lend their full support to the call by Lawyers without Borders — a volunteer organization that last year helped win the freedom of Amina Lawal, who had been sentenced to death in Nigeria for having a child outside marriage — that Libya's courts should order a fully independent, international scientific assessment of how the children were contaminated.

In 2004, an Editorial in this journal stated, with respect to the medics' case, that “Gaddafi has a chance to show the world that he now understands that true leadership means embracing justice, compassion and a respect for scientific evidence” (Nature 430, 277; 200410.1038/430277a). Two years on, we are still waiting, and Lawyers without Borders is right to hold President Gaddafi and the international community to account.

The scientific community has also been relatively silent on the case, perhaps in the hope that it would be sorted out by diplomacy. But the latter has not proved to be the case, and scientific leaders need to use all their influence urgently, as the fate of the medics will be sealed in the coming weeks. It is time not only to save the doctor and nurses, but also to defend a common vision of science and law in establishing the truth, above all other imperatives. Meanwhile, Gaddafi has the opportunity to put this affair behind him by giving the six an immediate pardon.