Brazil and the region - How do legislative party splits impact the president’s ability to govern?

James Bosworth (Boz) from Latin America Risk ReportNov 3, 2026

Brazil and the region - How do legislative party splits impact the president’s ability to govern?

I used AI to collect data and make lots of maps and charts while I thought about legislative coalitions. The maps and charts are about 75% Claude. The writing, analysis, and any errors are 100% mine.

Nov 3

Regarding Lula’s victory in Brazil’s election, I’ve heard some version of “but the president is going to struggle with Congress,” at least 100 times in the past week. It sparked thoughts about Brazil and the hemisphere. I had AI build some visuals to help me think about it.

To start, I asked Claude to map the formula for the effective number of parties onto the hemisphere. The numbers here are based on seats after the most recent legislative election results (so it doesn’t map party jumpers post-election). Brazil’s number is for the Congress that enters next year.

Some of this is useful. It shows that El Salvador is an effective one-party state while Brazil and Chile have some of the highest numbers of parties in the world. However, some countries don’t feel quite right. President Claudia Sheinbaum in Mexico, for example, has a fairly solid majority coalition, with the PT and PVEM acting almost as proxy parties for Morena, even as its legislative chamber technically has 3.5 parties.

So I built a separate map that is a more subjective attempt to answer the question, “Can the president get things through Congress?”

Some of these calls are borderline and should be debated. I definitely considered changing some of them.

Mexico’s and the DR’s reliable majorities are close to a rubber stamp, but I kept the democracies separate from the one-party states where the executive can de facto force the legislature to do their bidding. Costa Rica’s and Ecuador’s majorities are a bit less certain than Mexico’s. Honduras’s majority almost certainly will break apart and shift a category down if and when the Liberals challenge the president.
In Peru, I would have thought Fujimori was on a path to a reliable majority, but the lower house of Congress dealt her executive decree authority a blow. Similarly, in Colombia, there is a solid center-right to right majority in that Congress that should be a majority coalition for ADLE, but they have so far resisted the president.
Bolivia is approaching “uphill battle” territory. Kast’s recent errors are making Chile look questionable as well.

Ok, back to Brazil and its large number of parties. The legislature’s defining feature is the Centrão, or Big Center: a group of centrist parties that makes up a bare majority (257 of 513 seats) in the lower house. For today’s newsletter visuals, I asked for a split of the Centrão parties between those more likely to lean toward Lula and those who lean against him. Both halves are transactional. Those that lean against Lula can be fairly classified as center-right. Those that lean toward Lula may not be ideologically center-left. Perhaps it’s better to define them as “opportunist-centrists.” They are the parties far more willing to work with Lula and trade votes in exchange for ministries and deals. That creates a four-bloc Congress that makes the coalition challenge slightly (but only slightly!) easier to understand.

The basic takeaway: Lula’s coalition, with the overly bold assumption that every Lula-leaning Centrão deputy sticks with him, is 42 votes short of a majority in the lower house. For Lula to reach a majority on any of his initiatives, he must win over some of the center-right parties. However, for the opposition to attempt to impeach Lula, they have to win over a large number of the Lula-leaning Centrão against the president. It’s not happening any time soon. The numbers leave the lower chamber as a constant coalition forming struggle for both sides.

All of this assumes parties vote as blocs. Brazilian parties don’t. As an additional complication, Brazil has one of the world’s highest rates of party jumping. Some rules prevent formal shifts in the lower house, but legislators who don’t formally jump may adjust their voting patterns over the coming years depending on the deals they receive from other parties. Senators can jump parties at will.

For now, the Senate is much tougher for Lula and could go bold on institutional clashes against the judiciary. Removing a Supreme Court justice takes 54 votes, and the right plus the right-leaning Centrão already has 52. They need two of the 12 Lula-leaning senators, and MDB’s Alessandro Vieira has already said he backs impeaching STF justices. The big question is who the Senate chooses as its leader, because that person will have significant influence over whether any requests against the STF move forward.

One final note: I feel relatively certain several Brazil-focused analysts will argue about how I categorized and ordered the parties above into various blocs and coalitions. I know it’s an imperfect attempt. Brazil’s Congress is big, messy, and complicated. These charts are my starting point for trying to think about how Lula will interact with the Congress, but the congressional coalitions will certainly need to be remapped once the new Congress is seated next year and they actually start voting and deal-making.