Abstract
In this paper, we analyze the factors which influence legislator's willingness to vote in a Bipartisan congress. We construct two models to describe the voting behaviors of legislators. The main difference between two models is the numbers of members of two political parties. We analyze our models in finite and infinite cases. In the finite case, we derive the distribution of voting legislators and compare it with real data sets.In the infinite case, we derive a system of nonlinear differential equations for two models and we discuss the stability of the equilibrium points of nonlinear systems.