Introduction
What explains legislative effectiveness in presidential democracies? Most studies have focused on the United States (Butler et al. Reference Butler, Hughes, Volden and Wiseman2019; Clarke et al. Reference Clarke, Volden and Wiseman2018; Hitt et al. Reference Hitt, Volden and Wiseman2017; Volden and Wiseman Reference Volden and Wiseman2014, Reference Volden2018; Volden et al. Reference Volden, Wiseman and Wittmer2013), where party membership and majority status are central to explaining effectiveness. Comparative work remains scarce. One exception is Kerevel and Bárcena Juárez (Reference Kerevel and Bárcena Juárez2022), who examine effectiveness in Mexico’s Chamber of Deputies. They find that explanations developed for the US Congress do not travel neatly to Mexico, and they highlight a different mechanism: membership of opposition parties, rather than majority parties, is a key predictor of effectiveness in the Mexican case.
This article contributes to this comparative agenda by examining legislative effectiveness in Brazil. Unlike in the United States or Mexico, where parties structure effectiveness in different ways, the extreme fragmentation and weak programmatic commitments of Brazilian parties limit their ability to provide legislators with the information and coordination needed to be effective. In such settings, lawmakers often cannot rely solely on parties to provide policy expertise or to organize the majorities required for passing bills. I argue that legislative member organizations (LMOs) fill this gap.
LMOs are voluntary, cross-party organizations centered on specific political issues or themes. Examples in the United States include the Congressional Black Caucus and the Freedom Caucus, but in fragmented systems like Brazil’s, such groups play an even more consequential role. By pooling staff resources and coordinating across partisan boundaries, LMOs provide legislators with both policy and political information, serving as brokers of expertise and support. In this way, LMOs help solve collective action problems in legislatures where parties fall short.
Brazil offers an ideal case to test this argument. Its LMOs are considered institutionalized by Ringe et al. (Reference Ringe, Victor and Carman2013), and during the period of this study, the country reached unprecedented levels of party system fragmentation. The average effective number of parties (Laakso and Taagepera Reference Laakso and Taagepera1979) represented in the Chamber of Deputies between 2011 and 2018 was 12.2, and by 2017 it had reached 14.3. At the same time, research documents a sharp rise in congressional activism: since the mid-2000s, legislators have sponsored and passed more of their own bills than executive-sponsored ones, and have increasingly amended executive proposals (Almeida Reference Almeida2014; Hiroi and Rennó Reference Hiroi, Rennó, Alemán and Tsebelis2016; Rey Reference Rey2021, Reference Rey2023; Rey et al. Reference Rey, Spritzer and Brasilforthcoming). Lawmakers appear to be playing a more assertive role in the policy process than before.
Yet activism tells us little about legislators’ ability to be effective. To move beyond volume, this article examines the extent to which Brazilian lawmakers are, in fact, effective at advancing their initiatives through the legislative process. This raises a central puzzle: how can legislators achieve effectiveness in a context marked by extreme party fragmentation and weak party structures that, in other systems, typically organize lawmaking?
The analysis shows that affiliation with LMOs increases legislative effectiveness, but the effects are uneven across organizations and legislative roles. Quantitatively, legislators associated with strongly organized LMOs, particularly agribusiness and public security, score significantly higher on measures of effectiveness, especially as rapporteurs, while weakly organized LMOs, such as education and evangelical, yield null or negligible returns. These patterns suggest that organizational capacity is a decisive factor, as the technical resources, coordination structures, and cross-party networks of strong LMOs enable their members to navigate the legislative process more effectively than peers.
Qualitative evidence reinforces this finding by tracing how LMOs strategically place their members in key committees, mobilize votes through dense communication networks, and leverage their expertise to influence party leaders and the Chamber’s agenda. Parties continue to play a role in shaping effectiveness, but their effects are uneven across the system and do not consistently provide the information and coordination needed for lawmaking.
Taken together, the quantitative and qualitative analyses demonstrate that LMOs, when sufficiently organized, provide critical informational and coalition-building resources that complement and at times substitute for weak and inconsistent party structures, helping explain why some legislators in Brazil’s fragmented Congress are more effective than others.
This article proceeds as follows. The next section reviews the existing literature on legislative effectiveness. The following section develops the theoretical framework. I then present the research design and methodology before turning to the empirical analysis, which combines quantitative models and a qualitative case study. The conclusion summarizes the main findings and highlights directions for future research. Detailed information on data collection, management, and quantitative analyses is provided in the supplementary material.
Legislative Effectiveness in Comparative Perspective
Recent work on congressional politics in the United States (Butler et al. Reference Butler, Hughes, Volden and Wiseman2019; Clarke et al. Reference Clarke, Volden and Wiseman2018; Hitt et al. Reference Hitt, Volden and Wiseman2017; Volden and Wiseman Reference Volden and Wiseman2014, Reference Volden2018; Volden et al. Reference Volden, Wiseman and Wittmer2013) has focused on the effectiveness of members of Congress, defined as their ability to advance agenda items through the legislative process and into law (Volden and Wiseman Reference Volden and Wiseman2014, 18). These studies emphasize legislative experience, majority party status, and institutional leadership as central determinants of effectiveness. Legislators’ social connectedness also matters (Battaglini et al. Reference Battaglini, Sciabolazza and Patacchini2020), as does membership in party factions, which enhances the effectiveness of minority-party lawmakers (Clarke et al. Reference Clarke, Volden and Wiseman2018).
Outside the United States, Kerevel and Bárcena Juárez (Reference Kerevel and Bárcena Juárez2022) examine legislative effectiveness in Mexico’s Chamber of Deputies. Their findings diverge from the American case: legislators from opposition parties are more effective than those in governing coalitions, and legislative experience does not increase effectiveness. The one similarity across the two contexts is that legislators with leadership positions are generally more effective. Their study underscores that explanations drawn from the US context do not always travel well to other systems and highlights the need for alternative accounts in different institutional environments.
In Brazil, there are no systematic studies of legislative effectiveness per se. Existing scholarship has instead examined broader patterns of legislative activity and the balance of power between the executive and legislative branches. Early work emphasized executive dominance, with the president introducing and passing more bills than legislators (Figueiredo and Limongi Reference Figueiredo and Limongi1999). More recent research documents a trend toward greater congressional activism. Since the mid-2000s, Congress has passed more legislator-sponsored than executive-sponsored laws (Almeida Reference Almeida2014; Rey Reference Rey2021, Reference Rey2023; Rey et al. Reference Rey, Spritzer and Brasilforthcoming), and lawmakers have increasingly amended executive proposals (Hiroi and Rennó Reference Hiroi, Rennó, Alemán and Tsebelis2016).
These studies reveal that legislators are playing a more assertive role in the policy process, but they stop short of assessing how far, and with what variation, their initiatives advance. Activism may be visible in the introduction or approval of bills, yet this tells us little about legislators’ effectiveness across the whole legislative process. This article, therefore, examines the extent to which Brazilian lawmakers are effective and asks how such effectiveness is possible in a system marked by extreme party fragmentation and weak party structures that, in other contexts, typically organize lawmaking.
I address this puzzle by examining an underexplored explanatory factor: legislative member organizations (LMOs). LMOs are voluntary, cross-party organizations organized around specific policy themes. The first comparative study of LMOs (Ringe et al. Reference Ringe, Victor and Carman2013) finds they have little effect on legislative effectiveness in the United States, where strong parties already provide informational resources. In the next section, I consider whether this claim holds in Brazil’s fragmented party system, where parties often prioritize distributive or office-seeking goals over programmatic coordination (Rosas Reference Rosas and Mainwaring2010; Zechmeister Reference Zechmeister and Mainwaring2010). By shifting the analysis to this different institutional context, I assess whether LMOs can help fill informational gaps and shape legislative effectiveness.
LMOs and Effective Lawmaking
Legislators must cooperate to be effective, as the passing of bills requires the support of majorities. Cooperation is costly because legislatures face a high demand for, but low supply of, information (Ringe et al. Reference Ringe, Victor and Carman2013; Curry Reference Curry2015). This insight aligns with informational theories of legislative organization (Krehbiel Reference Krehbiel1992), which argue that institutions—especially committees—are designed to reduce policy uncertainty by generating and transmitting reliable information to the floor. While Krehbiel does not model “effectiveness” directly, a straightforward implication is that denser informational structures lower coordination costs and facilitate coalition building.
Legislators seek out two types of information. The first is policy information about various issues and their potential real-world consequences (Krehbiel Reference Krehbiel1992). The second is political information: information about who can participate at multiple legislative stages, their preferences, the institutional settings for action, and when actions can be executed. Effectiveness rests on combining policy and political information (Hitt et al. Reference Hitt, Volden and Wiseman2017).
Collectively, legislators can reduce the costs of cooperation by relying on organizations that pool and transmit information. Parties are a central source of such resources. They generate policy expertise through specialized staff and partisan think tanks (Echt Reference Echt2019; Luna et al. Reference Luna, Rosenblat and Toro2014), cultivate reputations for legislators as specialists in specific issue areas (Jones Reference Jones2005; Ponce Reference Ponce2013), and provide cues that reveal bargaining ranges and feasible outcomes across partisan lines (Aldrich Reference Aldrich1995; Cox and McCubbins Reference Cox and McCubbins2005; Curry Reference Curry2015). Party leaders also play a key informational role by coordinating internal preferences and supplying members with knowledge of other parties’ positions (Hall Reference Hall1996; Curry Reference Curry2015). In short, parties function as vertical informational structures that organize legislative cooperation around programmatic agendas.
Yet the Brazilian context makes this ideal-typical account less applicable. Party system fragmentation in Brazil is extreme (Lamounier Reference Lamounier1987; Mainwaring Reference Mainwaring1999; Mainwaring et al. Reference Mainwaring2018), and parties tend to prioritize distributive or office-seeking goals over programmatic coordination (Rosas Reference Rosas and Mainwaring2010; Zechmeister Reference Zechmeister and Mainwaring2010). Consequently, they often fail to supply the policy expertise or political information that legislators need to move proposals through the lawmaking process. In this context, lawmakers turn to sources of information beyond parties.
I argue that legislative member organizations (LMOs) serve this function in fragmented legislatures. Unlike parties or committees, LMOs cut across partisan boundaries and create horizontal networks for cooperation and coalition building. They enhance lawmakers’ effectiveness by offering platforms to learn about policy issues, identify colleagues with similar concerns, and set parameters for bargaining over policy outcomes. LMOs can also help assemble the majorities needed for policy approval. Participation in LMOs should therefore improve legislators’ effectiveness (hypothesis 1), since they supply both policy and political information. In this respect, my argument departs from Ringe et al. (Reference Ringe, Victor and Carman2013), who view LMOs primarily as providers of policy information and find little impact on effectiveness in the US context. By contrast, in Brazil’s fragmented party system, LMOs should matter more because they compensate for parties’ inability to coordinate information and build coalitions.
Hypothesis 1: On average, legislators associated with legislative member organizations will be more effective than legislators not associated with legislative member organizations.
The extent to which LMOs can fulfill these roles depends on their level of organization. Highly organized LMOs possess at least three of the following attributes: personnel, finances, activities, and physical resources. Highly organized LMOs can secure and employ staff to aid legislators in obtaining policy and political information. Thus, legislators associated with highly organized LMOs should more effectively advance bills through the legislative process (hypothesis 2).
Hypothesis 2: On average, legislators associated with strongly organized legislative member organizations will be more effective than legislators associated with weakly organized legislative organizations.
In summary, information is crucial for legislative effectiveness because it enables legislators to navigate the legislative process successfully. Access to policy and political information is essential for lawmakers to be effective. In fragmented party systems like Brazil’s, where parties are often unable to provide these resources, LMOs can fill the gap. As a result, legislators affiliated with highly organized LMOs are likely to be more effective than their peers.
Methodology
I test my theoretical expectations through a mixed-methods analysis of original data collected from extensive in-country fieldwork in Brasília, over nine months between 2018 and 2019.
Quantitatively, I use ordinary least squares (OLS) regression to estimate the relationship between legislative effectiveness and association with legislative member organizations (LMOs), controlling for covariates. I use log-transformed dependent variables in the model reported below and compute robust standard errors clustered by legislator. I also include fixed effects at the party level to account for party-specific characteristics.
To measure legislative effectiveness, I adapt Volden and Wiseman’s (Reference Volden and Wiseman2014) legislative effectiveness score (LES), which captures the relative share of all legislative activities in any legislature that can be attributed to each lawmaker. The scores consider and assign different weights to substantive and significant, substantive, and commemorative bills. Substantive and significant bills receive attention outside of Congress. In the United States, these bills have been the subject of an end-of-the-year write-up in the Congressional Quarterly Almanac. In Brazil, I identify these bills as those that have been reported in the newspapers O Estado de S. Paulo and Folha de S. Paulo. Commemorative bills provide renaming, commemorations, private relief of an individual, and the like. All other bills are substantive.
I propose two LESs focused on the Chamber of Deputies: one measuring bill sponsors’ effectiveness and another measuring bill rapporteurs’ effectiveness. Like in the United States, sponsors introduce bills. In Brazil, however, rapporteurs play an unusually consequential role in shaping legislative outcomes. Rapporteurs draft the official reports that recommend approval, rejection, or amendment of bills. These reports strongly influence how committees and, in many cases, the floor decide on a bill (Santos and Almeida Reference Santos and Almeida2005). Rapporteurs therefore act as gatekeepers and policy brokers, even for bills they did not sponsor. Although rapporteurship is a compulsory activity, deputies who are effective at completing their reports, building coalitions, and guiding proposals through the process can leave a significant imprint on lawmaking. This institutional feature makes rapporteurs’ legislative effectiveness analytically distinct from, but complementary to, sponsors’ effectiveness. Explanations about how each score is calculated, as well as a fuller discussion of the advantages and limitations of the rapporteurship measure, can be found in Appendix A.Footnote 1
I rely on two sources of data to measure association with LMOs. The first is the Agribusiness Parliamentary Front (FPA), which has compiled a ranking of all deputies based on their loyalty to the organization between 2015 and 2018. This allows me to create the best available measure of LMO association: a continuous variable ranging from 0 to 1, with 1 indicating the most loyal legislator.
The second is the Departamento Intersindical de Assessoria Parlamentar (Diap), which identifies association with the three other LMOs (public security, evangelical, and education) between 2015 and 2018. For these cases, association is coded as a binary variable. The Diap relies on consistent rules to classify legislators rooted in prior professional expertise or political trajectories that motivate LMO participation. Although less precise than continuous measures, binary coding is the best available option given data constraints, highlighting the trade-off between precision and coverage in measuring LMO association. Using this data, I create a dichotomous variable indicating individual membership in these three LMOs. A full explanation of both variables is provided in Appendix B.
I add the following control variables to my statistical models: party affiliation, committee participation, government-opposition, institutional positions, and legislator characteristics (gender, education, and alternate legislators). A complete list of these and other controls, along with their respective explanations, can be found in Appendix C.
The statistical models directly test hypothesis 1 by comparing the legislative effectiveness scores of legislators with LMO ties to those without such ties. To evaluate hypothesis 2, I classify agribusiness and public security as strongly organized LMOs, and education and evangelical as weakly organized. This classification is based on the presence of at least three organizational attributes—personnel, finances, recurrent activities, and physical resources—documented in Table 1 in Appendix B. Comparing estimated effects across these categories provides a test of whether organizational strength conditions the association between LMOs and legislative effectiveness.
Qualitatively, I examine three data sources. First, data from 74 semi-structured interviews with legislators, legislative staff, LMO members and coordinators, and civil society representatives were collected to explore the roles of political parties and LMOs in aiding legislative effectiveness. Second, data were collected through participant observation notes as I followed the daily activities of one legislator in Brasília. Third, archival data were obtained from congressional and legislative member organizations related to the activities of the same legislator. These qualitative materials allow me to trace the mechanisms through which LMOs influence lawmaking, illustrate how organizational resources are mobilized in practice, and provide contextual evidence that complements and deepens the statistical tests of hypotheses 1 and 2.
Results
Quantitative Analysis
Figure 1 presents the results of the fixed effects OLS models that examine the impact of association with LMO on bill sponsorship and rapporteurship legislative effectiveness scores, controlling for all the covariates discussed above and in Appendix C (see also Appendix C for full results). Consistent with hypothesis 1, LMO association is linked to higher LESs.
Coefficients of LMO Association on Legislative Effectiveness (2015–18).
Source: OLS models with logged dependent variable reported in Appendix C. The bars represent 95% (model 1) and 90% (model 2) confidence intervals—robust standard errors clustered by the legislator. Fixed effects at the party level are also included to account for party-specific characteristics. Strong LMOs = agribusiness, public security; Weak LMOs = education, evangelical.
Consistent with hypothesis 2, positive effects are concentrated in strongly organized LMOs. For agribusiness, the association coefficient is positive and statistically significant in the bill rapporteurship model (and negative but insignificant for bill introduction). All else being equal, legislators associated with the agribusiness LMO during their tenure are expected to have a rapporteurship effectiveness score 42% higher than those without such ties. Public security also shows positive and statistically significant effects: association increases legislative effectiveness scores by 36% for sponsors and 41% for rapporteurs. By contrast, education and evangelical LMOs exhibit null or negative effects, with no statistically significant coefficients (full results in Appendix C, Table 4).
To give substance to the size of the effects, it is useful to translate the coefficients into expected changes for a median deputy. In the sponsorship model, the coefficient for the public security LMO (0.305) indicates that, for an otherwise similar legislator, affiliation with that LMO corresponds to an increase of about 0.31 points in the logged sponsorship score. Applied to the median sponsorship value (0.41), this represents a meaningful upward shift—especially in a distribution in which half of the Chamber scores below that threshold and many lawmakers cluster near zero output.
The magnitude is even more apparent in the rapporteurship model. The public security LMO coefficient (0.342) and the agribusiness LMO coefficient (0.348) both imply gains of roughly 0.34 points in the logged rapporteurship score relative to legislators without these affiliations. When benchmarked against the median rapporteurship score (1.80), these shifts represent nontrivial increases in legislative productivity. While the absolute values are modest, their relevance becomes apparent when placed in the context of a legislative environment in which effectiveness is difficult to achieve and the distribution of outcomes is highly skewed. In other words, being an effective lawmaker in the Brazilian Chamber is rare and highly concentrated. Against this backdrop of low and very unequal effectiveness, the increases associated with LMO participation are substantively meaningful and cannot be overlooked.
The stronger and more consistent effect of the public security LMO across both models likely reflects the high salience of crime and violence in Brazilian politics. Public security is one of the most pressing concerns for voters and a central theme in electoral campaigns, which gives deputies associated with this LMO opportunities to advance their visibility and credibility both as sponsors and as rapporteurs. By contrast, the agribusiness LMO represents narrower but highly organized economic interests, whose influence tends to manifest more in technical negotiations within rapporteurships than in bill introduction.
The party coefficients provide only limited evidence that parties structure legislative effectiveness, and where they do, the effects are small and uneven. In the bill sponsorship model, almost all party dummies are statistically indistinguishable from the reference category, with the exception of the Workers’ Party (PT), whose deputies sponsor slightly fewer bills on average. In the rapporteurship model, again most parties show no clear effect, although Brazilian Socialist Party (PSB) legislators stand out with higher rapporteurship scores, and a few other parties (such as the Solidarity (SD), and the Progressive Party, (PP)) display only borderline positive associations. Taken together, these results suggest that while partisan affiliation still matters at the margins for specific parties and roles, party effects are weak and inconsistent across the system and do not substitute for the more robust informational and coalition-building advantages associated with LMO participation.
These statistical models also reveal other determinants of the legislative effectiveness of Brazilian deputies. All else being equal, legislators who associate with some legislative member organizations (i.e., the agribusiness and public security), occupy institutional positions (party leadership, committee chairmanship, or simply committee participation), are not alternates, and are better educated, have higher LESs.
Importantly, the coefficients on variables capturing association with the government coalition are both negative and positive and are statistically significant. Government coalitions that do not share motives and objectives may not cultivate the necessary conditions for their legislators to become more effective. This might be particularly true during the time frame analyzed in this article—in 2016, President Dilma Rousseff faced impeachment, suggesting that her government coalition might lack internal cohesion.
Qualitative Analysis
This section traces the lawmaking activities of one legislator (Evair Vieira de Melo) as a bill sponsor associated with a highly organized LMO (agribusiness).Footnote 2 De Melo was first elected in 2014 as a representative of the state of Espírito Santo. He ran for office at the request of the state’s rural sector by joining the Green Party (PV). De Melo was a deputy leader of his party between 2016 and 2018. He is closely associated with the agribusiness legislative member organization. Between 2015 and 2018, he served as the LMO’s institutional coordinator.
His LES as a sponsor is 10.32, much higher than the average LES of all sponsors (0.81). Within one congressional session, two of his bills became law. This is no small achievement as, on average, only 0.5% of bills introduced by deputies pass within the same congressional session. One of the bills is 3859/2015, legalized the commercialization of artisanal products, such as cheese and sausage, across states and municipalities.
After de Melo introduced the bill on December 8, 2015, it was referred to three committees:Footnote 3 the Economic Development, Industry, Commerce, and Services Committee, the Agriculture, Livestock, and Rural Development Committee, and the Constitution, Justice, and Citizenship Committee.
At the Economic Development, Industry, Commerce, and Services Committee, deputy Silas Brasileiro was appointed as the bill’s rapporteur. Although committee chairs formally choose rapporteurs, de Melo’s chief of staff noted that sponsors often informally influence choice. Accordingly, de Melo’s office asked Silas Brasileiro, who was close to the agribusiness LMO,Footnote 4 to be the rapporteur. The committee chair agreed.
However, Brasileiro’s tenure as rapporteur was short-lived, and he was soon replaced by Covatti Filho, also strongly associated with the LMO.Footnote 5 A new rapporteur, Covatti Filho, was also closely associated with the agribusiness LMO (he received 0.50 in the LMO ranking, which ranges from 0 to 0.88; thus, he was highly associated with the LMO), took over Brasileiro’s job as a rapporteur. He presented his report in favor of bill approval on June 28, 2016.
The bill was then referred to the Agriculture, Livestock, and Rural Development Committee. The rapporteur was Nelson Meurer, again associated with the agribusiness LMO (his score with the LMO is 0.16). His favorable report was presented to the committee on October 5, 2016.
De Melo employed a procedural maneuver that brought his bill to a floor vote as quickly as possible. With the support of rapporteur Fabio Sousa—associated with the agribusiness LMO (score 0.13) and serving as rapporteur on behalf of the Committee rapporteur on the floor—the bill was approved on March 20, 2018, just over two years after its introduction.Footnote 6
As de Melo’s chief of staff explains, the LMO used its network of lawmakers to support de Melo’s actions in pursuing bills like 3859/2015. The three rapporteurs who analyzed it in committees (Covatti Filho, Nelson Meurer, and Fabio Sousa) were associated with the LMO.
I am in the WhatsApp group of the directors of the LMO. There is another one just for people in press relations. And another is technical, focusing on the issues. We exchange information all the time. When one of our bills is about to be voted on, I message all groups saying: there is a bill by Mr. de Melo to be voted on today, we need help. They mobilize everybody to vote in favor of the bill. (Interview 8).
Indeed, highly organized LMOs, such as agribusiness, influence voting decisions in committees and on the floor—aiding their lawmakers’ efforts in the legislative process—through two informal mechanisms.
The first refers to LMOs’ efforts to place their members on key committees aligned with their policy interests (interviews 8, 22, 37, 56, 57, 73, 75, 78, and 81). Agribusiness LMO members sit on the Agriculture, Constitution and Justice, Tax and Finance Committee, and Environment Committees (interview 22). According to an LMO coordinator, “Those are the committees through which our bills always pass. Today, our vice president is the chair of the Tax and Finance Committee. We have the majority in the Agriculture Committee. We have several members in the Environment Committee.” (Interview 22). A legislative consultant adds, “The agribusiness LMO mobilizes yearly so that the Environment Committee is not only in the hands of environmental legislators. They want to promote equilibrium in this committee so that they have a say when a bill is voted.” (Interview 37).
Per Chamber rules, committee chairs are elected by their committee members. However, these positions are often negotiated behind the scenes, making committee elections symbolic. LMOs can act behind the scenes to appoint committee chairs who are sympathetic to their positions on policy issues. One LMO coordinator recalls instances when a party informally appointed a committee chair to the Agriculture Committee who was not sympathetic to the agribusiness LMO. “The LMO goes against his appointment and helps elect someone else. LMO members discuss if the name is bad [in terms of guaranteeing the LMO interests] and launch their candidate” (interview 22).
The second mechanism refers to the capacity of highly organized LMOs to influence the decisions of non-LMO legislators in key leadership positions—in particular, the decisions of party leaders and the president of the Chamber—by appealing to their expertise. Several respondents point to the role of LMOs in seeking out party leaders to add their proposals to the legislative agenda and in adopting the LMO’s policy preferences in committee and on the floor. These interviews suggest that LMO members act within their parties to persuade party leaders to support LMOs (interviews 8, 21, 23, 41, 56).
Per the Chamber’s rules, the weekly and monthly legislative agendas are determined by party leaders and the Chamber’s president. These are the most powerful formal actors in the Chamber’s legislative processes. According to a legislative staff member, LMO presidents often persuade these actors to include their bills on the agenda. “The president of the agribusiness LMO, for instance, goes to the president of the Chamber and says: This topic is hard for us, please help us with this” (interview 23). About the president of the Chamber, one legislator adds that he “knows when an LMO is important. He knows the mobilization power of an LMO. He plays this game” (interview 82).
Only party leaders have the formal power to direct votes in committees and on the floor. However, LMO members seek to influence their voting decisions in two ways. Either party leaders listen to LMO members to decide, or give the decision-making task to LMO members themselves. “This happens when the party leader does not know the policy that will be voted on,” explains a legislative staff member. He adds, for example, “When the MDB has to vote about agriculture, the person who does it is not its party leader, but the agribusiness LMO president, who is also a member of the MDB. It is also easier for him to convince other deputies than the party leader” (interview 78).
This perspective is confirmed by another legislative staff member, who recalls seeing a powerful performance of the agribusiness LMO on the floor, with LMO members “informally directing votes as if they were party leaders” (interview 73). This staff member adds: “The formal power always belongs to the party leader, but on the floor, sometimes it becomes very clear that there is another cleavage operating that is not the party’s.”
The agribusiness LMO also monitors agribusiness-related bills to offer its members policy and political information in the form of executive summaries. The one about bill 3859/2015 includes a bill summary, a technical justification of its importance, and orientation for LMO members on voting. The LMO has its own think tank, Instituto Pensar Agro, maintained by 48 agribusiness interest groups. Created in 2011, it provides technical and logistical support to the agribusiness LMO (founded by landowner lawmakers during Brazil’s Constitutional Assembly in 1988) (interview 22). In addition, the LMO runs its own news agency, Agência FPA.
Furthermore, the agribusiness LMO’s network is not active only on WhatsApp. Once a week, its members meet for a luncheon at the LMO’s building to discuss the legislative agenda of the Chamber of Deputies. Members meet in a large conference room to discuss existing bills, potential bills, voting decisions, and meetings with executive branch representatives (including the president). Legislative staff from LMO members’ offices attend the meetings.
Notably, the agribusiness LMO also played a role in the Senate approval of bill 3859/2015. De Melo’s office arranged the selection of rapporteurs in various committees in the upper house by relying on the LMO to identify senators aligned with the topic. After Senate approval, the bill required presidential sanction by Michel Temer. De Melo’s chief of staff says that the agribusiness LMO is “fundamental” in this step of the legislative process. “Part of the Ministry of Agriculture was against this bill because veterinarians thought they would lose their autonomy in the regulation process. The LMO pressures the executive branch. If necessary, it even articulates a meeting with the president to pressure him” (Interview 8).
Conclusion
This article introduces legislative effectiveness scores (LESs) for both bill sponsors and bill rapporteurs in Brazil’s Chamber of Deputies. It uses them to evaluate whether and how legislative member organizations (LMOs) shape individual effectiveness. The quantitative results directly support hypotheses 1 and 2. Association with LMOs is linked to higher legislative effectiveness overall. Crucially, these gains are concentrated among strongly organized LMOs: public security membership is associated with higher effectiveness for both sponsorship and rapporteurship, while agribusiness membership raises effectiveness for rapporteurship but not consistently for sponsorship; weakly organized LMOs (education, evangelical) exhibit null effects. These patterns indicate that organization capacity—not merely the existence of an LMO—conditions whether informational and coordinating benefits translate into lawmaking gains.
The qualitative evidence clarifies the mechanisms behind those associations. The agribusiness case traces how an LMO’s organizational assets (dedicated staff, technical briefs, regular coordination meetings, and a sectoral think tank) and networked coordination (WhatsApp groups; weekly caucus lunches) reduce information and transaction costs throughout the process.
Two mechanisms recur; first, placement and alignment in key venues: LMOs help seat allies on pivotal committees and informally shape rapporteur selection, aligning technical expertise and preferences at the points that structure amendments and gatekeeping. Second, agenda access and vote direction: LMO leaders leverage their credibility with party leaders and the Chamber presidency to secure agenda placement and, in areas where parties lack deep expertise, to informally steer voting cues. These mechanisms map directly onto the quantitative asymmetries: technical, negotiation-intensive roles, especially rapporteurship, benefit most from the dense informational and brokerage capacity of strong LMOs. Parties still matter, but unevenly; their effects are smaller and more inconsistent than those of the structured, cross-party networks that LMOs provide, consistent with a fragmented and weakly programmatic party system.
Substantively, the Brazilian case shows that organizationally strong cross-party networks can substitute for missing party-supplied information and coordination, shifting who is effective and how. Methodologically, treating rapporteurs as consequential actors is essential for capturing effectiveness in multiparty presidential systems where committees and reporting power are central to policy change. Future work should extend these integrated tests to additional LMOs and policy domains, incorporate measures of blocking effectiveness, and adapt interest-area LESs to assess whether LMO-linked gains are concentrated within their issue portfolios.
Supplementary material
To view supplementary material for this article, please visit https://doi.org/10.1017/lap.2025.10039
Acknowledgments
The author disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by Syracuse University and the Center for Effective Lawmaking at the University of Virginia.
Competing interests
Beatriz Rey declares none.
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