Beyond the Presidency: The Power of Congress in Latin America

Despite times of democratic backsliding, executive power is not on the rise everywhere. Across Latin America, congresses have been reshaping how presidentialism operates, often utilising significant decision-making authority. Yet these dynamics vary, resulting in diverse legislative trajectories and balances of power across countries.

• Despite low public trust and high party fragmentation, several legislatures have pursued institutional change by reshaping their own structures, revising rules to rebalance power vis-à-vis the executive, or attempting revisions but ultimately retreating in the face of presidential power.

• On 12 April Peruvians elect a president and a new Congress amid pronounced presidential instability. The legislature has reasserted itself by passing an important reform reintroducing bicameralism – a shift intended to increase stability and reduce fragmentation, but which may create new problems.

• In October, Brazil will carry out presidential and congressional elections. The incoming president will find a Congress grown more resolute over recent years – particularly in budgetary matters. This institutional change reflects increasing executive–legislative competition and a shift towards more power-sharing.

• In October 2023 Argentine voters elected Javier Milei, a political outsider with a radical economic reform agenda but meagre congressional support. Early signs of legislative pushback, including rule-change attempts, faded after 2025 midterm success strengthened presidential leverage over Congress.

Policy Implications

Across Latin America’s long-standing presidential systems, the balance of power between the executive and legislative is shifting. For policymakers and international actors, engaging more closely with congresses will be essential. Legislatures may alter or block policy agendas, raise costs for coalition-building, lengthen negotiation timelines, and increase uncertainty in foreign policy arrangements.

Why Keeping an Eye on Latin American Legislatures Is Critical

In Latin America, the president is by far the most visible political actor, and presidential elections are the most salient political events. By contrast, legislatures command far less public attention, even though they are also directly elected and typically at the same time as presidents. Moreover, public opinion data consistently show that congresses not only suffer from lack of interest but also persistently enjoy much lower levels of trust and approval. This relative lack of appeal endures despite legislatures being central institutions in representation, lawmaking, executive oversight, and participation in the election of authorities. Moreover, there are three compelling reasons to turn our attention to Latin American legislatures at this moment in time.

First, in an era of democratic backsliding, there are contradictory views on Latin American legislatures. On one hand, they are often portrayed as structurally vulnerable to subordination. Presidents accommodate or neutralise them through concessions, patronage, or manipulations of the law as part of executive aggrandisement (Bermeo 2016) or personalisation of executive power (Richter et al. 2025). On the other hand, parliaments in Latin America are much stronger than those of other world regions (Wilson and Woldense 2019: 592), though their power has slightly declined in the last several years (Ishiyama 2024). Recent developments in the region acknowledge the negative side of such strength – sometimes referred to as congressional authoritarianism (Sosa-Villagarcia, Incio, and Arce 2025) – and underground parliamentarism (Freeman 2022). These divergent assessments reflect the diversity of legislatures across the region, which cannot be reduced to two opposing types.

Second, whereas all legislative bodies are endowed to create and modify the law, some are currently using this power to change themselves. Legislatures collaborate with the executive power in policymaking, intervene in the composition of judicial bodies, and authorise or in some cases approve constitutional reforms, among other functions. Also, they have the sole power to decide on the rules for their own internal organisation – for example, those concerning the speed of voting processes and the time slots assigned for speeches – which can increase or reduce opportunities to deliberate and express dissent. Further, legislative organisation has crucial effects on representative democracy: having a bicameral legislature slows the lawmaking process but can improve deliberation and representation, as well as reinforcing checks and balances. Institutional changes would seem unlikely in contexts of high party fragmentation; yet, intriguingly, some highly fragmented legislatures have managed to pass alterations that suggest an expansion of their institutional power. Although spectacular changes such as the return to bicameralism attract most public attention, more incremental ones – and the interests behind them – are equally important to examine.

Third, when legislatures are characterised by excessive political fragmentation, this composition may reflect a representation crisis in which no political offer manages to appeal to a broad segment of the electorate. Latin American presidentialism sometimes circumvents this problem by forming governing coalitions; in some legislatures, voting and legislative fragmentation do not impede political alignments along policy or ideological lines. Thus, presidential minority situations in Congress do not automatically translate into hyper-fragmentation or legislative dominance. Legislative power is relational, and presidential status critically shapes these relations. Not all outsiders and party-minority presidents enter office on equal footing: some command electoral momentum, public support, or institutional leverage outside the legislature. The president’s capacity to exercise leadership, resist changes, and signal strength, as well as his or her willingness to negotiate and compromise, are important factors in shaping legislative power. Legislatures calibrate their strategies accordingly. Moreover, their clout is not static: it evolves across contexts, underscoring the need to better understand how and in what ways they are empowered.

Three Congresses, Three Paths

To exemplify current trends, we have selected three politically fragmented congresses working with minority presidents. These show quite different congressional statuses: In Peru, presidential and legislative elections take place simultaneously every five years. This unicameral congress of 130 members holds the upper hand, representing what we term a dominant legislature. In Brazil, the president and the bicameral congress of 513 deputies and 81 senators interact at eye level, each wielding significant influence. This assertive congress interacting with strong presidential authority is what we call a challenging legislature. In Argentina’s bicameral congress, the 257-member Chamber and the 72-member Senate renew by half and one third, respectively, every two years. Political change is conceived of as being gradual in this congress, and presidents command the policy agenda by offering concessions in exchange for support – a condition we describe as a reactive legislature (as in Morgenstern 2002).

Peru: The Dominant Legislature

The Peruvian Congress is often perceived as the dominant branch of government, even though the Constitution does not formally grant it such primacy. The president and Congress are elected by popular vote for concurrent five-year terms. However, Peru’s system of government has been described as a parliamentarised presidentialism because, while preserving the core institutional features of presidential systems, since the nineteenth century it has gradually incorporated mechanisms of legislative control typically associated with parliamentary regimes. Such mechanisms include, for example, ministers’ interpellation, the censure of a minister or the entire cabinet, the vote of confidence, and the presidential power to dissolve Congress if two cabinets are denied confidence.

As we show below, congressional dominance has often been characterised by how congressional decisions have impacted presidential stability. However, it is also evident when we look at the legislative production as well as the approval of a constitutional reform that will change the congressional structure after the election of the new Congress on 12 April 2026. Congress has reached the required majorities and supermajorities for these key decisions, despite deepened political fragmentation and the increased weakness of party labels.

First, presidential removal, a constitutional tool designed for exceptional circumstances, has been used recurrently and regularly. To understand this growing power of Congress, it is necessary to look at recent history. In 2016 Peru experienced its first clearly divided government: the ruling party secured only 14 per cent of the seats in Congress, while the opposition controlled 56 per cent. Although since 2001 no president had governed with a stable congressional majority, from 2016 on, presidential terms became increasingly unstable. The Peruvian Congress moved from using instruments such as the interpellation and censure of ministers to directly removing presidents from office on the grounds of “permanent moral incapacity,” a constitutional provision that allows Congress to declare the presidency vacant with a two-thirds vote. Using this mechanism, Congress approved three presidential removals, pushed two presidents to resign before the end of their terms, and recently even removed the president of Congress – who had assumed the Presidency of the Republic according to the constitutional line of succession – through a vote of censure. In short, since 2018 Peru has had eight presidents instead of the two that would have normally served during that period. Political conflict only intensified after the first of those forced resignations, that of President Kuczynski in 2018, and the forced dissolution of Congress ordered by President Vizcarra in 2019, a move later upheld by the Constitutional Court, but one that motivated the newly inaugurated Congress in 2021 to strengthen its muscle vis-à-vis the executive. The outcome of this tug-of-war was a dysfunctional system in which the distinction between government and opposition has eroded, undermining the effective functioning of political institutions.

Second, and as a consequence of executive instability, Congress has increased its leverage over the national agenda. For example, after the removal of President Pedro Castillo in 2022, Congress approved more than 200 laws by congressional insistence. It was in fact the period in which most laws were passed, but one revealing profound institutional weaknesses. According to the Constitution, members of Congress cannot introduce legislative initiatives that generate additional public spending. Those involving tax incentives or exemptions must be accompanied by an economic report from the executive, and the budget law – as well as any modifications to it – must originate in the executive branch. Since 2020, however, Congress has increasingly approved spending measures and budgetary changes without favourable executive reports. Examples include the creation of public universities, the appointment of personnel across public administration sectors, and increases in pensions. When vetoed by the executive, Congress has often enacted these measures via override, which requires an absolute majority – not a supermajority as is the case in other congresses. If the pattern of congressional spending continues, it may negatively affect Peru’s (rather renowned) macroeconomic stability in the future.

Third, a supermajority managed to pass a constitutional amendment to restore bicameralism. In the upcoming elections, voters will choose congresspeople for a Chamber of Deputies (130 members) and a Senate (60 members). This major institutional change is not as out of the blue as it may seem: the re-establishment of the Senate – Peru had a Senate until the constitutional reform of 1993 – has been debated since 2001. In 2018 President Vizcarra’s referendum on the matter was rejected by the people. Since 2022 several versions of this reform were debated and voted on in Congress, eventually producing a consensus around an institutional design that strengthened the Senate while subordinating the Chamber of Deputies in several areas, including legislative matters. In this asymmetric bicameralism with differentiated powers for the two chambers, senators cannot introduce bills, but they control the final legislative outcome. They may approve, modify, or archive bills passed by the Chamber of Deputies while no mechanism to override Senate decisions is foreseen in the text. In practice, the Senate has the final word in the legislative process. It will also appoint Constitutional Court judges, designate three members of the Central Bank’s board, ratify its president, and review emergency and legislative decrees issued by the Executive.

Will this form of bicameralism restore the quality of legislation and presidential stability? In our view, the missing back-and-forth system for the writing of legislation does not necessarily guarantee better legislation or a more robust deliberative process. The procedure for removing the president by declaring her/his permanent moral incapacity may aid stability, as it will now require two separate votes. Further, the introduction of a double electoral threshold for parties to obtain seats (5 per cent of seats and 5 per cent of valid votes at the national level) means that fewer than eight parties will gain representation, despite 38 party lists currently competing. This will be a significant reduction in fragmentation that may also raise questions about representativeness and the legitimacy of this reform. This brand-new congress may contribute to greater stability, but parliamentary support will still be required for the presidency to regain its institutional role.

Brazil: The Challenging Legislature

Brazilian presidentialism is characterised by a strong presidency and the formation of coalition governments whose purpose is to assemble congressional support in a highly fragmented bicameral legislature. However, presidentialism as we have always known it in Brazil has undergone cumulative changes both in its institutional rules and in the balance between branches of government that demonstrate the deliberate and incremental nature of Congress’s process of expanding its institutional capacities. Congressional power expansion deepened recently, during the politically weak presidency of Jair Bolsonaro and the COVID-19 pandemic.

Three long-term changes are noteworthy. First, one of the most important constitutional tools available to Brazilian presidents to influence the law-making process is the power to issue Provisional Measures (Medidas Provisórias, MPV), decrees with the force of law that can alter the status quo of laws and public policies, even though they may later be amended or rejected by Congress. Presidential decree-making has an extensive impact on legal and policy production and MPVs have frequently been revised by legislators. However, as early as 2001 Congress modified the rules governing MPVs to prevent a practice that had become common among governing coalitions – that of avoiding a congressional decision while allowing presidential decisions to remain in force through the indefinite reissuance of MPVs.

Second, another fundamental presidential power is the veto. In Brazil, presidents hold a full and a line-item veto. Via the latter, they can veto a portion of a bill passed by Congress that they do not agree with, while the other parts of the bill are immediately sanctioned into law. During the mid-1990s and into the 2000s, congressional leaders often refrained from scheduling votes on veto overrides, thereby allowing the president’s decision to prevail. However, in 2013 Congress amended its internal rules to ensure that presidential vetoes are automatically placed on the legislative agenda for voting.

Third, a more explicit move to strengthen Congress occurred with the revision of the executive’s budgetary powers. These powers, which were greatly expanded during the military regime (1964–1985), are strategic for presidential policymaking because the budget determines which policies are viable. Congressional strengthening occurred through the expansion of parliamentary prerogatives to reallocate resources in the budget bill across policies or government programmes whose funding is discretionary. These changes occurred incrementally. Initially, they were introduced via internal congressional decisions and annual budgetary legislation regulating the execution of federal spending. The turning point came in 2015 when the execution of individual parliamentary amendments (Constitutional Amendment 86 of 2015) and state caucus amendments (Constitutional Amendment 100 of 2019) became mandatory rather than merely authoritative, a move that significantly increased the resources allocated through these instruments. Moreover, Constitutional Amendment 105 of 2019 allowed the direct transfer of budgetary resources to state and municipal governments, bypassing the intergovernmental agreements that were previously used by the president to steer spending towards priority public policies and programmes.

More recent institutional changes occurred under Jair Bolsonaro’s (2019–2022) minority government, characterised by the lack of a clear governing agenda and the support of a heterogeneous and radical social coalition – economically liberal but socially conservative. This government was highly dependent on the partisan and bicameral coordination of congressional leaders to pass laws. In addition, the outbreak of COVID-19 during Bolsonaro’s second year in office led Congress to adopt emergency measures to mitigate the socioeconomic effects of the pandemic. Bolsonaro’s government maintained a denialist stance, and Congress was compelled to take institutional steps to remain operational under emergency conditions. To do so, it modified its internal rules to sustain and accelerate legislative activity and to produce urgent decisions. On one hand, by anticipating the risks associated with an increase in presidential emergency powers, Congress shortened the time for MPV consideration – a move challenged by the president before the Supreme Court but ultimately upheld. Congress also took the initiative to approve emergency financial assistance programmes for vulnerable populations, as well as support for small and medium-sized enterprises. Finally, it moved to ensure the flow of budgetary resources to subnational governments, preventing paralysis at those levels in the adoption of measures to address the health crisis.

On the other hand, the discretion of congressional leaders in managing legislative decision-making increased in this context. The Remote Deliberation System (Sistema de Deliberação Remota), an emergency and exceptional system enabling remote voting during the pandemic, became integrated into the routine operation of both chambers. This occurred without the formal revision of their internal regulations; in fact, this system has continued to operate via ad hoc decisions by the Speakers of the legislative chambers without formal approval by the plenary, which has facilitated its strategic use by the Speakers. This has made the deliberative process more unpredictable and reduced opportunities for dissent and debate.

In connection with the previous point, the strategic control of the legislative agenda by the Speakers of the chambers has expanded with the increasing frequency of extraordinary deliberative sessions and the near disappearance of ordinary sessions. Resolution 21 of 2021 of the Chamber of Deputies further strengthened the Speaker’s control over the timing of debates and the allocation of speaking time in plenary sessions, thus restricting the use of key procedural instruments available to individual deputies and parliamentary minorities.

All these changes have enabled congressional strategies that allow legislators to compete with the executive in shaping public policy and that amplify the distributive effects of parliamentary alliances. An important effect of this shift is the growing blockage of the executive’s legislative agenda, occurring simply through congressional inaction on MPVs, which causes them to expire without a decision. Twenty-two per cent of non-budgetary decisions under the Bolsonaro government and 39 per cent under the first two years of the administration of President Luiz Inácio Lula da Silva expired in this way. As a result, the Lula government has increasingly been forced to use ordinary legislative initiatives, which procedurally compete with legislators’ own proposals. Although this route may still be effective, it entails a reduction in the powers that presidents have to control the legislative agenda, since they can no longer benefit from the fast-tracking procedures attached to MPVs, engendering a historically significant shift in presidential decree power in Brazil.

Argentina: The Reactive Legislature

As in Brazil, Argentine presidents have the power to issue decrees with the force of law – known as Necessity and Urgency Decrees, or, DNUs (Decretos de Necesidad y Urgencia) – and to partially or totally veto laws. For a workable institutional game, presidents must send their policy proposals to Congress for discussion and accept that bill approval involves concessions and amendments. For their part, at least some legislators must be willing to acknowledge the president’s agenda and potentially provide support, instead of using the heavy institutional weapons of blockage straight away.

The nature of executive–legislative relations was particularly uncertain when Javier Milei won the presidency in 2023. Observers expected to see both unilateralism (by way of DNUs) and institutional conflict (leading, for example, to the issuing of vetoes). Not only was Milei the first Argentine president in 40 years of democracy who arrived in power without a real party structure and without reaching at least one-third of seats, alone or with allies, in at least one of the chambers: he also engaged in a populist discourse against the “political caste” (which he qualified as parasitic, corrupt, and useless) and presented an ambitious plan of draconian economic reforms. In the tug-of-war over power that took place in the first two years of his term, the president ultimately prevailed. While the legislative branch displayed some moments of assertiveness, this spirit dissipated following the president’s electoral success in the congressional elections of October 2025. Despite attempts, no significant legal change occurred that might have produced a more balanced share of power between president and Congress in the long run.

Prior to the midterm elections, Milei advanced his legislative agenda by using DNUs extensively and relying on powers delegated to him by Law 27742 of 2024. This law bundled a comprehensive package of economic, fiscal, energy, labour, criminal, and administrative reforms into a single piece of legislation. (While Congress did approve it, it was only after a six-month legislative process and a version that significantly limited the scope of the original executive proposal.) In addition, and despite constitutional limits on DNU use, the mega-DNU 70 of 2023 contained 366 articles and declared a broad public emergency in economic, financial, fiscal, administrative, social, tariff-related, and energy matters up to December 2025. This DNU provoked objections in both Congress and the courts. In March 2024 the Argentine Senate voted to reject the decree by a large majority, but the Chamber of Deputies failed to do so, the decree therefore remaining in force. Some sections, though, have been challenged in the courts.

The contentious nature of Milei’s agenda is reflected in the seven total vetoes issued in 2025 – considering that just 17 laws were passed that year – three of which were subsequently overridden by the legislature. But the major challenge was the standing of the DNUs. Different from the regulation of Brazil’s Provisional Measures, which require explicit approval to remain in force, in Argentina, DNUs take effect immediately and remain in force unless both chambers explicitly reject them by resolution (as set out in Law 26122 of 2006). This advantage did not prevent Milei facing the first rejection of a DNU since the approval of Law 26122 (DNU 656 of 2024, which allocated additional funds for the discretionary use of the Intelligence Secretariat). In addition, Congress initiated the amendment process of Law 26122 to require explicit congressional ratification of DNUs within a maximum of 90 days. This would have considerably strengthened the power of Congress in the legislative process, but the bill is still awaiting its third reading in the Senate, and its approval appears unlikely since the midterm congressional elections of October 2025 strengthened the presence of the president’s party and its allies. Congress may once again have missed an opportunity to assert its institutional authority.

The winds of change were blowing in the extraordinary sessions of summer 2026, particularly with the approval of the labour reform in February (Law 20744). The head of La Libertad Avanza, the president’s party, in the Senate excitedly described this success as “the most reformist Congress Argentina has ever had” and called the labour law “a collective construction with all senators.” In the multiparty composition of Congress, Milei’s party added votes from other blocs – such as the centre-right PRO (the party of ex-president Mauricio Macri) – that joined the presidential bloc en masse after the October 2025 elections, as well as from some members of the Unión Cívica Radical (Radical Civic Union, UCR), and several provincial forces. Thus, the electorally empowered president managed to get approval for a reform that increases labour-market flexibility, though he had to make concessions to governors (such as removing a corporate tax cut that would have reduced provincial revenues) and the unions (such as preserving contributions to union funds).

Milei has seen his congressional support considerably increased. Informal rules for the internal parliamentary distribution of power should further protect the advancement of the presidential agenda as it is customary that the presidencies of the most important legislative committees are granted to the ruling party and its allies, even though committee seats are distributed proportionally among parties. Committee presidencies have gate-keeping power that can be used to block unwanted legislation. A reactive Congress will be functional in the remaining two years of his mandate, but the previous two showed that congressional support is not a given. Congress can always assert its prerogatives, as it did last year by seeking to derogate DNUs, insisting on keeping its laws regarding overturning vetoes, and summoning the committees to meet when committees’ authorities deliberately evaded such meetings.

Institutional Changes and Persistent Tensions

While recent studies have pointed to a weakening of legislatures globally in the face of executive aggrandisement, the Latin American legislative landscape looks more varied. We examined three Latin American congresses that have followed disparate paths. All have engaged with constitutional or procedural reforms with different scopes and outcomes, but all sought to alter the status quo of relations with the presidency. Each path, while addressing current dysfunctionalities, simultaneously engenders new challenges.

In Peru, the re-establishment of bicameralism including a new upper chamber with important legislative powers appears to be a sweeping solution to chronic executive instability, among other problems. However, there is uncertainty about how the new set of rules will help presidential authority recover and, particularly, whether Congress will support the idea of an institutionally stronger presidency. Moreover, it is unclear if and how the new institutions will provide solutions to other deep problems, such as repairing relations with the electorate. While institutional changes reshape legislative power, they do not necessarily address the underlying sources of disaffection. In fact, the problem may not reside in the legislature itself, but in the nature of the parties that comprise it.

In Brazil, Congress has led a long-term process of modifications of procedural rules to approve legislation, block or modify executive decisions, and advance its own legislative agendas. It has managed to become more assertive in pursuing its legislative goals and promoting distributive gains with potential electoral payoffs for legislators. The downside of this more balanced distribution of power is the increased cost of governing. Presidents are facing tougher bargaining conditions and negotiation dynamics, in which pork-barrelling and concessions to Congress and parties are the norm to avoid stalemate. Rule changes reflect deeper fractures and intensifying intra-elite competition in the current context of polarised presidential competition. As a result, coalition presidentialism’s modus operandi is moving towards more congressional power in the policymaking process.

In Argentina, despite the context of party fragmentation and the reorganisation of political forces, political competition has continued to unfold largely within established decision-making rules that mostly favour the president. The attempt to change the law regulating Necessity and Urgency Decrees and the activation of congressional procedural rules that had previously been seldom used were flashes of Congress’s assertive behaviour. But since the president retained public support in the 2025 midterm elections, the status quo has tended to prevail, and Javier Milei has managed to organise congressional work among allies. This certainly improves governance conditions but diminishes controls to prevent abuse of power and much needed deliberation on controversial policies.

Parliaments are the forum par excellence for democratic debate, the expression of dissent, and the search for consensus; however, reforms that would strengthen these core functions are not those currently driving the reform agenda. Instead, recent institutional changes point to a growing role of law-making bodies in shaping and contesting policymaking that reflects intra-elite shifts in the distribution of power. These changes result in legislatures seeking to expand their influence over policy decisions. As a result, policymaking becomes more contested and increasingly shaped by intra-elite bargaining, something that requires a more sustained engagement from domestic and international policy actors.

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