The primary goal of this research is to determine the size of the drug-involved offender population that could be served effectively and efficiently by partnerships between courts and treatment. Despite a growing consensus that substance abuse treatment promotes desistance, few arrestees receive sufficient treatment through the criminal justice system to reduce their offending. Strict eligibility rules and scarce resources limit access to treatment, even in jurisdictions that embrace the principles of therapeutic jurisprudence. The result is that existing linkages between the criminal justice system and substance abuse treatment are so constrained that at best only small reductions in crime can be achieved. The limited access to treatment for the criminal offender population appears to be based on subjective judgments of both the risks of treating offenders in the community and the benefits of treatment. Risks are assumed to be high for most offenders, and the benefits of treatment are assumed to be low. As a result, almost all drug-involved arrestees are determined to be ineligible for participation in community-based treatment programs. An important question for the nation's drug policymakers is whether a substantial expansion of substance abuse treatment would yield benefits from reduced crime and improved public safety. A related question is whether evidence-based strategies can be developed to prioritize participation, given limited resources.