A wavering equilibrium theory of subsystem politics is developed to di
stinguish between three types of subsystem politics. I suggest that su
bsystem players' ability to control the policy agenda varies with chan
ges in subsystem politics. This article uses correlation analysis with
data on bill sponsorship and referral to examine the impact of subsys
tem variation on policy making in three subsystems. I find that subsys
tem political variation is associated with changes in subsystem player
s' ability to control bill introduction and referral.