Box 1. What can pressure by the scientific community achieve?

Taye Woldesemayat, an academic who was freed from an Ethiopian jail in 2002 after sixyears, says he is living proof that campaigning by scientists for colleagues whose human rights have been compromised can be effective.

"In prison, I felt hopeless at the beginning; I knew they were going to kill me," he told Nature. "But then the letter-writing campaigns began, and as the letters started flowing in [to the Ethiopian government] it was fantastic, I knew I could get out."

Woldesemayat was jailed in Addis Ababa in 1996 on charges of terrorism and armed conspiracy against the state. Human-rights organizations concluded that he had simply called for greater social justice and democracy.

The American Association for the Advancement of Science (AAAS) and the US National Academy of Sciences weighed in alongside human-rights bodies such as Amnesty International, and the Ethiopian High Court overturned the charges in 2002. After his release, Woldesemayat moved to the United States, although the Ethiopian government is again pursuing him after he helped form an opposition party last December.

Defending the human rights of scientists, engineers and physicians is a little-known sideline of many scientific organizations. Every year they campaign on hundreds of cases.

The biggest players are the AAAS, which launched its Science and Human Rights Program in 1993, and the US National Academies' Committee on Human Rights (CHR). Also in 1993, the CHR created a global action network of 70 science academies, although only 40 participate actively. "Nobel prize winners and scientists, especially when they represent many different countries, have the power to influence," says Dagfinn F011esdal, a philosopher at Stanford University in California and a member of the network's board.

Carol Corillon, director of the CHR, says science bodies vet cases carefully before taking them on. "If Amnesty International has adopted the case I feel fairly comfortable, as they do good research," she says. "But we always try to get verification with the families, the lawyers, and people we know in the country."

Once a case is adopted, lobbying is mainly through private political contacts and letter-writing to politicians. The impact of such campaigns is hard to measure, admits Corillon. "About three-quarters of our cases get resolved, but it's difficult to know what role, if any, our action played."

Corillon feels that scientific academies are often better placed to act in private. But, she adds, "Often a carrot-and-stick approach is most effective. I think that without having the public pressure as well on many cases, we wouldn't have had success."

Even when campaigns do not resolve a case, they are crucial, says Claude Cohen-Tannoudji, a 1997 Nobel laureate in physics and board member of the academy network. "It's important that when someone is persecuted, the government doing the persecution knows that the world is watching."

D.B.