A number of scholars assert that State and Federal courts are in a new relationship, labeled the "new judicial federalism." This new relationship began in the 1970's when the Burger Supreme Court started to retreat from and limit the Warren Court's expansive interpretations of Federal civil liberties protections. Under this relationship, State courts have developed an independent body of State constitutional law in criminal procedure, often engaging in "State constitutional policymaking" by interpreting provisions of their State bills of rights more broadly than the U.S. Supreme Court's interpretation of analogous provisions of the U.S. Constitution. The study reported in this article relied on 528 State high court decisions from 25 States in which the courts interpreted criminal procedure guarantees in their State constitutions. It investigated trends in this behavior across States and within individual States. The study found that rates at which State courts have extended criminal procedure rights beyond Federal levels have varied significantly over the first 25 years of the "new judicial federalism," both overall and in individual jurisdictions. Contrary to speculation in the literature, levels of policymaking have increased slightly in more modern years, and more States are actively extending rights compared to earlier years. This article concludes with possible explanations for these findings and their implications for the future of State constitutional policymaking in criminal procedure. 3 tables and 31 references