A framework is introduced for evaluating static micro-analytic theories in dynamic macro-political settings. Within the framework, two theories of lawmaking are compared. Analytically, the predictions of the theories are remarkably similar- almost to the point of being observationally equivalent. However, analysis focusing on critical, theory-specific regime changes provides an opportunity for some discrimation. The findings provide some support for both partisan and nonpartisan theories, the relative strength of which seems to depend upon roll calls selected for analysis.