The article discusses the general development of State separation theory, and decisions regarding the constitutionality of the Federal Speedy Trial Act (FSTA) are examined to provide a basis for the analysis of State court opinions, some of which expressly rely on the FSTA cases. An investigation of cases involving State speedy trial and speedy disposition acts or rules addresses whether statutes mandating speedy decisionmaking by the courts impermissibly encroach on the judicial power. Also analyzed is the argument that a court's creation of a speedy trial rule unconstitutionally invades the legislative or executive realms. The other two issues considered are the claim that a speedy trial statute is an invalid legislative infringement on the courts' power and the contention that a speedy trial provision is an unconstitutional intrusion on the prosecutor's power. 336 footnotes.