Jewish law permits the release of a thousand terrorists, including those guilty of murder, in exchange for captive Cpl. Gilad Shalit, Rabbi Ovadia Yosef, the spiritual mentor of Shas, ruled this week. Yosef's son David, who heads the Yechaveh Da'at Beit Midrash in Jerusalem, drafted the halachic decision, which was later approved by his father. Yosef's opinion, was first published in the haredi weekly Hamishpacha. "It is imperative to free as many terrorists as necessary to save Shalit's life," wrote Rabbi David Yosef. "In life and death situations like this one, we must not make calculations precisely on how many terrorists should or should not be freed or whether they have blood on their hands or not." In a telephone interview with The Jerusalem Post, David Yosef said that neither he nor his father had consulted with military or intelligence experts before issuing the decision. "The purpose of the decision is to give halachic backing to the government if it makes the decision to free terrorists," he said. "If the experts decide that the risk of letting those terrorists go is worth taking, they should know that they are acting in accordance with Jewish law." David Yosef said that he did not think publicizing the ruling would weaken Israel's negotiating position. "I don't think anyone in the government doubted we would be willing to make a hostage swap," he said. "Besides, I do not rule out military action as a means of freeing Gilad Shalit." Yosef said he did not address the question of reservists Eldad Regev and Ehud Goldwasser because there was some doubt as to whether they were still alive. Ovadia Yosef's decision is unlikely to have an impact on the cabinet's actions, but it will serve as an official directive for Shas ministers, said a Shas source. The foundations for David Yosef's ruling were laid by his father in two precedents: the 1976 hostage crisis in Entebbe, Uganda, and the 1985 Ahmed Jibril deal. In both cases Ovadia Yosef ruled it was permissible to release terrorists, including murderers, in exchange for Jewish hostages whose lives were in danger. In the case of Entebbe, a hostage swap was preempted by an IDF commando operation that freed the Jewish hostages. In the May 1985 Jibril deal, Israel released 1,150 Palestinian terrorists, including Hamas founder Sheikh Ahmad Yassin, in exchange for three Israeli POW's. Critics of the deal said it sparked the first intifada, which began two years later. But David Yosef rejects this. "No one can prove that the release of those prisoners is what caused the first intifada," he said. Yosef said that immediate danger to a Jewish hostage takes precedence over the potential future danger that freed terrorists will commit additional attacks, especially since deterrence, targeted killings and other military action might prevent these future attacks. In principle, Jewish law prohibits paying an exorbitant price for freeing a Jewish hostage. The rabbis feared that doing so would encourage more kidnappings. Rabbi Meir of Rotenberg (1215-1293), who was kidnapped in Germany, famously issued a ruling prohibiting his followers to pay his ransom. He died in captivity. David Yosef said the Rabbi Meir precedent was irrelevant because, unlike Shalit, his life was never in danger.