摘要：Despite the vast literature on social security reform there are relatively few studies that analyze the participation of representatives coming from the union movement in the decision-making process. This article aims to fill part of that gap in Brazilian academic production on unionism and public policy. In situations in which unionist representatives support the ruling party, does the union bloc tend to defend the specific interests of their base of social representation or to follow the guidance of the party coalition of which they are part? The study addresses this research problemby analyzing the participation of the union bloc in the decision-making process of a social security reform, Proposal of Amendment to the Constitution, Article 40 (PEC 40), during the first term of Luiz Inácio Lula da Silva's government. The main findings of the study confirm the thesis of party predominance. In an institutional political scenario in which party discipline prevails, unionist representatives and senators tend to follow the guidance of the party coalition even under contrary pressures from their electoral base. The research sheds light on the relations involved between the Executive and Legislative branches, in the process of changing public policy, in which a government considered to be allied imposes losses for specific sectors of the union base, notably the active and inactive public servants of the federal government, states and municipalities.
