Arguments against experiments include violations of nonparticipants' rights by denying them equal access to treatment, the legality of government involvement in research activities, and the arbitrariness of random selection. In rebuttal, it is contended that the criminal justice system has no obligation to provide services to everyone and therefore excluding some persons from treatment programs is legal. Furthermore, in those cases where the experiment has no positive value, the nonparticipants are not being denied any beneficial exposure. It is important that government agencies be able to measure the value of programs and services to prevent waste. Random selection is used because it avoids discrimination on the basis of subject traits. Differences in the treatment of participants and nonparticipants in experimental conditions are generally not excessive and do not usually last for extended periods of time; thus, the principle of like treatment for like case is not violated. In the past, there have been no successful cases of suits based on discrimination during criminal justice experiments and it is unlikely that such a case will be mounted. Researchers wishing to adopt experimental designs in the face of objections should become familiar with legal defenses of the experimental method, should demonstrate sensitivity to the issue, and should enlist the support of those who have cooperated with research efforts in the past. Thirty-three court cases are cited and fourteen references are provided.