This chapter examines the role of the Brazilian Congress in civil–military relations, emphasizing its limited influence despite significant potential. The study focuses on the Lower Chamber Committee on Foreign Relations and National Defense (CREDN). CREDN has exhibited both active and passive years in its oversight of defense policy. While several institutional developments in the 1990s and 2000s could have enhanced legislative control over the military, including professionalization and specialization, these were undermined by the merging of the National Defense Committee with the Foreign Relations Committee in 1997. This merger diluted the focus on defense issues, resulting in an excessively reactive or benign stance in legislative oversight. The chapter employs Qualitative Comparative Analysis (QCA) to identify conditions associated with CREDN’s activism and passivity, finding that factors such as electoral cycles and executive-legislative relations significantly impact the type of oversight. The findings suggest that despite formal prerogatives, the Brazilian Congress has not extended its influence significantly over defense policy, remaining largely acquiescent to the decisions made by the Ministry of Defense and the armed forces.