By Igor Andrade and Fernanda Arbex, Partners at Innova Assuntos Públicos*
The 2026 elections will bring the renewal of two-thirds of the Federal Senate, a cycle that repeats every eight years. Under this model, 54 of the 81 seats will be contested, and each voter will be entitled to cast two votes for Senate candidates in their respective state. This rule, embedded in the institutional design of the House, alters the electoral dynamics compared to races in which only one seat is at stake, requiring parties and coalitions to engage in more careful ticket engineering.
Most senators whose terms are ending are expected to seek reelection, while others are considering bids for state governorships or even the Presidency of the Republic — as is the case of Senator Flávio Bolsonaro (PL/RJ). This movement is accompanied by intense party realignment, given that the Senate plays a central role in Brazil’s institutional framework: beyond serving as the reviewing chamber of the lower house, it is responsible for holding confirmation hearings and approving appointments to the Supreme Federal Court (STF), regulatory agencies, and other authorities, as well as having the authority to prosecute and try STF justices in impeachment proceedings.
For the federal government, the Senate election is considered a top priority. In the event of presidential reelection, the prevailing assessment within the Presidential Palace is that governability from 2027 onward will depend directly on the composition of the Senate. A more fragmented or predominantly opposition-led Senate could impose significant costs on the Executive’s legislative agenda and strategic appointments.
On the opposition side, the objective is equally clear: expand representation in the chamber to strengthen an agenda of greater institutional oversight, particularly over the Supreme Federal Court. As the Senate votes on judicial nominations and may initiate proceedings against justices, the race for Senate seats takes on contours that go beyond the traditional legislative dispute.
In this context, former President Jair Bolsonaro has begun a strategy of structuring state-level tickets for the Senate. In states governed by center-right leaders, he has sought agreements under which he would nominate one candidate on the ticket, while the governor would indicate the second. The rationale is to maximize the presence of direct allies in an election that offers two seats per state.
However, this strategy is already facing tensions. In states such as Santa Catarina and the Federal District, right-leaning figures outside the Liberal Party (PL) — whose candidacies had previously been consolidated — have encountered obstacles following the imposition of two candidates aligned with the former president. In such cases, the risk is the emergence of independent or dissident candidacies, which could fragment the electorate and alter the outcomes expected by national leadership.
Within the governing coalition, the strategy has followed a different direction. The focus has been on building alliances with center and center-right figures who demonstrate electoral viability, even if this entails reducing space for more ideologically aligned left-wing candidates with lower competitiveness. The rationale is pragmatic: to prevent the Senate from being dominated by lawmakers resistant to any form of negotiation with the Executive. The priority is to support candidates who, while independent, maintain institutional channels open to dialogue.
The renewal of two-thirds of the chamber also introduces a relevant electoral variable. Since voters cast two ballots, ticket formation requires at least minimal ideological convergence and complementarity between candidates. Unbalanced tickets or those marked by strong internal competition may lead to vote dispersion, opening space for centrist candidates capable of capturing the so-called “second vote” from both left- and right-leaning voters.
In summary, the 2026 Senate race is likely to be as strategic as the presidential election itself. Beyond defining temporary majorities, the contest may reshape the balance of power among branches of government and directly influence institutional stability and policymaking capacity in the next political cycle.
For the productive sector and international investors, understanding this dynamic will be essential to anticipate scenarios and assess medium-term risks and opportunities.
*This text does not necessarily reflect the opinion of the CCBC and is the sole responsibility of the author who signed this content.
