Penal rehabilitationism has been in eclipse since the early 1970s.[1] Treatment efforts seemed to offer only limited hope for success.[2] Relying on treatment to decide the sentence seemed also to lead to unjust results--for example, to excessive intrusion into offenders' lives in the name of cure.[3] Recently, however, there have been hints of an attempted revival. Some researchers claim striking new successes in treatment techniques. These successes, Ted Palmer concludes in a recent survey of treatment methods, suggest that rehabilitative intervention has gained increased moral and philosophical legitimacy, and that it is no longer the case that rehabilitation should be secondary to punishment...whether for short- or long-term goals.[4] Some penologists--for example, Francis Cullen and Karen Gilbert--argue that a revival of the penal treatment ethic could help lead to a gentler and more caring penal system.[5] Interestingly, such arguments sometimes come from penologists of the left[6]--who once had been so critical of treatment-based punishments.[7] There is by no means unanimity, however, even from these sources. Some researchers--for example, John Whitehead and Steven Lab in their recent survey of juvenile treatments[8]--continue to be quite pessimistic about those treatments' effects. Some writers of the left--for example, Thomas Mathiesen[9]--still strongly resist treatment as the basis for sanctioning. Nevertheless, there is enough ferment to prompt the question in our title, Should penal rehabilitationism be revived? Reinstatement of a treatment ethic would raise a number of questions. How much more is known about the treatment of offenders now than was known a few years ago? How often can treatment give us answers about how severely to sentence convicted offenders? Is treatment really as humane as it is made out to be? How fair is it to base the sentence on an offender's supposed rehabilitative needs? Rehabilitationism went into eclipse some years ago partly because it could not answer those questions satisfactorily. Are better answers available today? We approach these issues from heterogeneous viewpoints. One of us (von Hirsch) is a philosophical liberal, and has long been an advocate of the desert model.[10] The other (Maher) has a more left and feminist orientation,[11] and is skeptical of a retributive penal ethic. In our present discussion of the new rehabilitationism, we will not be assuming another articulated sentencing philosophy. What we agree on are the questions, not the answers. Questions of Effectiveness During the late 60s and the 70s, critics of penal treatment sometimes were tempted to assert that nothing works. The phrase now haunts them, and confuses analysis. It implies that the main problem of treatment is that of establishing its effectiveness; and that treatment can be declared a success once some programs are shown to work. Both assumptions are erroneous. Even when treatments succeed, their use to decide sentencing questions raises important normative questions (discussed below). And occasional successes are not enough. The last large-scale survey and analysis of treatments, undertaken by a panel of the National Academy of Sciences,[12] is over a decade old. It was distinctly pessimistic in its conclusions: when subjected to close scrutiny, few programs seemed to succeed in reducing offender recidivism. Since then there has been continued experimentation, and successes have been reported.[13] Some treatment advocates, such as Paul Gendreau and Robert Ross, have suggested that such findings show that rehabilitation has been revivified.[14] Perhaps, however, caution is in order. The extent of recent treatment successes remains very much in dispute--as witness a recent debate among researchers who have surveyed juvenile treatment programs.[15] A source of continuing difficult is that the whys of treatment (that is, the processes by which successes are achieved) are seldom understood. …