Drug courts solve problems, namely, reducing drug use and recidivism. The current research attempts to answer the question of how to ensure program fidelity and therefore optimize the efficacy of drug courts. Justice professionals and scholars have recognized that there are multiple internal and external threats that could undermine the drug court operation. At this point, the mechanism(s) by which threaten factors affect drug court program fidelity has been neither theoretically modeled nor empirically tested. In the present study, using a national sample and the Structural Regression Analysis (SRA), we found collaboration and judicial decision making are the most important factors for maintaining drug court program fidelity. This is because collaboration and judicial decision making can mediate the threats and challenges from many quarters, including the lack of information sharing and evaluation, treatment, operational support, and community and political support.