Introduction
The proportional electoral system is the model adopted by Brazil for the election of federal, state, and district deputies, as well as city councilors. This system aims to guarantee the representation of parties in proportion to the votes obtained, strengthening political plurality and democratic representation.
However, even with the goal of ensuring equity between votes and seats, this model has always faced questions regarding its complexity, effectiveness, and fairness in the distribution of seats, especially concerning so-called leftover votes.
Recently, the topic returned to the center of legal and political debate with the judgment of Direct Actions of Unconstitutionality (ADIs) 7228 and 7263, which questioned legislative changes in the way these surplus seats are distributed. The decision of the Supreme Federal Court (STF) had a direct impact on the composition of parliamentary blocs and the future of the Brazilian proportional representation system.
This text aims to explain how the proportional representation system works in Brazil, what electoral leftovers are, the legal basis for ADIs 7228 and 7263, and the practical effects of the Supreme Court's decision.
I – The Brazilian Proportional System
The proportional system seeks to elect candidates proportionally to the total votes their parties or coalitions receive. To this end, the 1988 Federal Constitution mandates that elections for legislative positions occur through a representative system that combines voting for the party list with voting for the individual candidate.
In proportional elections, valid votes (excluding blank and null votes) are added together to obtain the electoral quotient—which is the minimum number of votes required for a party to be entitled to a seat. Then, each party's votes are added together, and this total is divided by the electoral quotient, resulting in the number of seats obtained directly.
However, since the number of seats is rarely filled exactly through this division, what are called electoral leftovers arise—vacancies that remain after the application of the electoral quotient. The distribution of these leftovers has been the subject of legal regulation and, more recently, intense judicial dispute.
With the enactment of Law No. 14.211/2021, there was an important change in the way electoral surpluses are distributed. This reform altered articles 108 and 109 of the Electoral Code and established a new criterion for accessing surpluses:
II – The 2021 electoral reform and leftover votes
Only parties that had reached at least 80% of the electoral quotient and whose candidates individually obtained at least 20% of the electoral quotient would be eligible to compete for the remaining seats.
The legislator's stated intention was to strengthen the larger parties, prevent party fragmentation, and discourage the proliferation of parties that depended exclusively on coalitions or vote-getters.
However, this new legal requirement has been harshly criticized for restricting the participation of medium and small parties in the race for remaining seats, contradicting the principles of equality, proportionality, and political pluralism guaranteed by the Federal Constitution.
III – ADIs 7228 and 7263: The legal questions
Direct Actions of Unconstitutionality 7228 and 7263, filed respectively by Rede Sustentabilidade and Progressistas (PP), challenged the constitutionality of the new model for distributing leftover electoral votes.
Among the arguments presented, the following stand out: violation of equality, disproportionate restrictions on access to elected office, disrespect for the principle of popular sovereignty, and weakening of political pluralism.
According to the parties that filed the lawsuits, the restriction imposed by the new wording of Article 109 of the Electoral Code created an artificial differentiation between parties, violating the principle of equal treatment among political groups. Furthermore, the additional criteria (80% of the electoral quotient + 20% individual) unduly restricted the possibility of electing representatives, especially for smaller parties.
By limiting the validity of votes cast for candidates and parties that did not reach the required percentages, the rule frustrated the will of the voter, thus compromising the presence of smaller parties in parliament, and undermining democratic balance and diversity of representation.
The trial of the Direct Actions of Unconstitutionality (ADIs) began in March 2024 and was concluded in the first half of 2025. The Supreme Federal Court, by majority vote, declared unconstitutional the requirement that parties reach 80% of the electoral quotient to compete for remaining seats, maintaining only the requirement that the candidate have obtained 20% of the electoral quotient individually.
Justice Ricardo Lewandowski (later replaced by André Mendonça during the continuation of the trial) argued that the 80% restriction was incompatible with the proportional system established in the Constitution, as it imposed a disguised barrier clause.
The Court understood that the legislature cannot exclude from the dispute over leftover electoral votes parties that, although they did not reach the quota, still have significant votes, since these leftover votes are intended precisely for the most faithful representation of the popular vote.
It was reaffirmed that the party performance clause is already constitutionally mandated and cannot be expanded through ordinary legislation, and can only be done eventually via constitutional amendment.
The decision has retroactive effects, which generated discussions about the possible recount of votes from the 2022 elections. After the filing of motions for clarification to remedy this jurisdictional gap, seven federal deputies elected in 2022 were replaced by candidates who had been passed over based on the rule declared unconstitutional.
Thus, following the Supreme Court's decision, all parties participating in the election can compete for remaining seats, provided that the candidate reaches 20% of the electoral quotient individually. This increases the chance for smaller parties to win legislative seats.
By allowing more parties to participate in the final allocation of seats, the decision preserves the proportional and pluralistic nature of the electoral system, valuing political diversity and popular sovereignty. With fewer requirements for competing for remaining seats, there is less risk of valid votes becoming ineffective, increasing the effectiveness of the vote.
From now on, parties will have more incentive to field competitive candidates, since they will no longer depend exclusively on the party's collective performance to access leftover votes.
IV – Criticisms of the Supreme Court's decision
As is typical, there are supporters and critics of the Supreme Federal Court's decisions. Among the points of greatest contention, it is highlighted that the three Direct Actions of Unconstitutionality (ADIs) analyzed by the STF were filed only after the 2022 election, when the result was already known.
In short, it is argued that there would be a change in the rule (and the outcome) of the game at an inopportune moment, so that, by knowing the beneficiary of a decision, we would not only be facing a legal analysis, but also a political valuation.
Final Words
The Supreme Federal Court's ruling on ADIs 7228 and 7263 reaffirmed central principles of Brazilian democracy: representativeness, party equality, and popular sovereignty. By declaring the requirement of 80% of the electoral quotient for access to remaining seats unconstitutional, the STF prevented the proportional system from being transformed, in practice, into a disguised majoritarian model.
This decision strengthens the legitimacy of the electoral system and safeguards political pluralism by allowing a greater diversity of political forces to access Parliament, even when they do not reach the full electoral quota.
With this, Brazil reaffirms its commitment to a proportional, open, and fair model of representation, in which each citizen's vote has real weight in the formation of the Legislative Branch.
BIBLIOGRAPHIC REFERENCES
DE JESUS, Marcelo. The Brazilian Proportional Electoral System from the Perspective of Critical Mathematics Education. Dialética Publishing House, 2025.
PINHEIRO, Victor Marcel. The temporal effectiveness of the STF decision in the case of leftover votes. Jota. Available at: https://www.jota.info/opiniao-e-analise/colunas/observatorio-constitucional/a-eficacia-temporal-da-decisao-do-stf-no-caso-das-sobras-eleitorais
RODAS, Sérgio. Rule for dividing leftover electoral votes applies to the 2022 elections. CONJUR. Available at: https://www.conjur.com.br/2025-mar-13/regra-de-divisao-das-sobras-eleitorais-vale-para-eleicoes-de-2022-diz-stf/.
ROMÃO, Maurício Costa. The judgment of the ADIs regarding leftover votes amidst the clash between Congress and the Supreme Court. Jota. Available at: https://www.jota.info/opiniao-e-analise/artigos/o-julgamento-das-adis-de-sobras-de-voto-em-meio-ao-embate-congresso-vs-stf.
