In Brazil’s legislative process, political exchanges between the government and legislature is an essential feature. This article focuses on the role of the president and political parties in Brazil’s national legislative process. Because nonideological factors influence voting, roll calls do not suffice for estimation of legislators’ policy preferences. In this article, we derive a spatial model of voting in which voting behavior is induced by both ideological motivations and coalition dynamics and develop a multilevel ideal-point model implied by the spatial voting model. After the proposed model is applied to the analysis of roll-call votes in the Brazilian Chamber of Deputies between 2003 and 2006, coalition dynamics is found to influence the voting behavior of legislators. We also confirm the finding in previous studies that the ideological alignment of political parties in the legislature contrasts with the perceived positions.