Last week, the Supreme Court overturned a 2004 law that mandated the establishment of a privately run prison, which was subsequently built near Beersheba. The main thrust of the judgment was that it delegated sovereign powers that are not constitutionally subject to delegation. Prisons are extremely expensive, and the hope of the legislature was that private prisons could be run at much lower cost. The single prison authorized by the bill would have served as a pilot. Economically, it would show if cost reductions would indeed be forthcoming; ethically, it would show if prisoners' rights would still be adequately safeguarded. The ruling itself suffers from the usual lacunae of major Supreme Court rulings, including that the case was brought by "public petitioners," who lack all standing in the case. It also had the customary grandstanding of Supreme Court President Dorit Beinisch, who made the unusually egregious (even for her) claim that "the court is called upon to express the values anchored in the social consensus." Consensus is the responsibility of the political process, not the judicial one. Even so, the idea of a private prison does carry the danger of delegation of powers, which in our modern system of government are inherently sovereign ones. It is true that in the distant past private prisons were common, as were private police forces and brigades of mercenary soldiers. But there are good reasons that the latter two categories have disappeared from modern democratic society - and perhaps those reasons apply to the first category as well. Recent Nobel laureate Oliver Williamson studied why some activities take place in firms and others in markets. By the same token, we can ask what activities ideally should be in the public sector and which in the private sector. One critical factor, the one with the most salient constitutional relevance, is the cost of mistakes. Newspapers columnists are fairly harmless at their worst; so we are left to write whatever we want (and bear the consequences). Restaurants can give people food poisoning; so while anyone can open a restaurant, they are subject to health regulations and inspections. When we progress to the kind of far-reaching powers we want to give a police force or an army to enable them to do their job, it is clear that the potential for abuse is immense. Public-sector bodies have a high degree of public oversight. In Israel, nothing that goes on in the police force can be kept from the public security minister and relevant Knesset committees. But the inner workings of private groups can be obtained only through a prolonged legal process. From that point of view there is a strong argument that functions with a high potential for abuse should remain government monopolies. This oversight comes at a cost, which is why many functions with a low potential for abuse do not belong in the public sector. The potential for abuse in running a prison is immense. As the court pointed out, everything a prison does is a violation of people's rights. A prison, by definition, denies people their liberty. Prison discipline often requires imposing punishment without any trial or other legal safeguards, and prisoners are a very vulnerable group whose access to justice is more limited than that of an ordinary citizen. Prisoner abuse was a factor in the transfer of a number of private prisons abroad to public administration. The opposite problem also exists: that warders will treat some prisoners too lightly due to their political or economic clout. Public oversight certainly does not eliminate these problems, but it does create important safeguards for appropriate and equitable treatment. There are also nonconstitutional grounds for wondering if a private prison is a good idea. One thing the public sector does extremely badly is innovate. So there are strong grounds for privatizing anything requiring innovation. But since prison technology is little changed since the incarceration of Joseph in Egypt 4,000 years ago, this justification for privatization seems to be missing from the incarceration industry. The private sector is also good at cutting costs through competition (though often this is through innovation). But I do not think we will see meaningful private competition in the Israeli prison sector anytime soon. The entire prison population here is about 20,000, which could be housed in three or four large US-style jails. I can understand the desire of the Knesset to limit spending on prisons, and certainly a pilot project is a prudent way to explore the idea of privatization in this sector. However, privatization of prisons raises serious questions of just and equitable treatment, and I see few compelling opportunities for public benefit. firstname.lastname@example.org Asher Meir is research director at the Business Ethics Center of Jerusalem, an independent institute in the Jerusalem College of Technology (Machon Lev).