Medina v. California

Summary

The Court affirmed, holding that due process permits California to require a criminal defendant to prove incompetence to stand trial by a preponderance of the evidence and to retain a corresponding presumption of competence. Justice Kennedy's five-Justice majority applied Patterson's historical and fundamental-fairness inquiry rather than Mathews balancing. Justice O'Connor, joined by Justice Souter, concurred in the judgment, maintaining that balancing remains appropriate but concluding that California's allocation could encourage cooperation and fuller production of competency evidence. Justice Blackmun, joined by Justice Stevens, dissented, arguing that the State must bear the burden of proving competence to adequately protect the fundamental prohibition against trying incompetent defendants.