Longitudinal trial court studies lack a simple model of system litigation. This essay advances the argument that models which attempt to explain either trial court behavior or changes in civil litigation have little explanatory power. Rather, a system mobilization model is needed that has the following paradigms: (1) a perception paradigm that produces awareness of matters that might be the subject of a conflict or dispute; (2) a paradigm that explains how these detected matters are socially constructed as potentially legal matters; (3) a legal mobilization paradigm explaining how legal agents or some legal subsystem is mobilized to handle some legal matters; (4) a process paradigm explaining how matters that enter the trial courts become matters for trial; (5) a trial court mobilization paradigm followed by (6) an appellate process paradigm. The development of such a model of system litigation will resolve some of the methodological as well as conceptual problems that currently beset research on trial courts. A number of these problems relating to the longitudinal study of trial courts are discussed.