Proportional Representation vs. Districts: The Brazil-US Test on Polarization

If you have turned on the news in the United States or Brazil anytime during the tumultuous election cycles of 2026, the feeling is identical: exhaustion. Voters in both hemispheres are staring down the barrel of legislative standstills, where governance seems to have taken a backseat to political warfare. The question keeping political scientists and furious constituents awake is whether the machinery of our elections—the very way we count votes—is engineering this rage.

To understand the root of this gridlock, we must look beyond the candidates and examine the blueprints of their power. The United States operates on a strict single-member district system (often known as First Past The Post), while Brazil utilizes an open-list Proportional Representation (PR) model. Both democracies are struggling with extremism, but the mechanism by which it manifests—and potentially, the way out of it—differs radically.

The American Experiment in Binary Choices

The United States Congress is currently paralyzed not by a lack of ideas, but by the structural rigidity of the electoral map. In a single-member district system, the winner takes all. If a candidate gets 50.1% of the vote in a district, they represent 100% of that population. The loser, and their 49.9% of supporters, get zero representation.

This dynamic creates a powerful incentive toward a two-party duopoly, a phenomenon political scientists call Duverger’s Law. In 2026, this has resulted in a binary "us versus them" mentality. Because there is no room for third parties to gain legislative traction, polarization occurs inside the major parties rather than between them. We see the "civil war" within the GOP and the struggle for the soul of the Democrats, but the general election offers no nuanced outlet for a voter who might be fiscally conservative but socially progressive. You are forced to pick a team, and the teams are increasingly hostile toward one another.

Furthermore, the rise of partisan gerrymandering has cemented this. Most House districts in the US are "safe," meaning the real election happens in the primary. In a low-turnout primary, the most ideologically rigid voters—the base—hold the keys to the kingdom. This incentivizes politicians to reject compromise. If you work across the aisle, you risk a primary challenge from the extreme flank. Consequently, the US system does not just encourage polarization; it incentivizes obstructionism as a campaign strategy.

Brazil’s Fragmented Mandate

Cross the equator, and Brazil offers a chaotic counterpoint. In October 2026, Brazilians will likely vote again under an Open-List Proportional Representation system. Here, the country is divided into large multi-member districts—usually the states themselves. São Paulo, for example, sends 70 representatives to the lower house. Parties put up large lists of candidates, and seats are allocated based on the percentage of the vote each party receives.

If a small party gets 5% of the national vote, they get roughly 5% of the seats in the legislature.

On the surface, this sounds like a recipe for inclusivity. Indeed, Brazil has a proliferation of parties—over 20 are currently represented in the National Congress. This allows for niche voices to be heard. However, the impact on polarization is distinct. Brazil does not suffer from the same "binary paralysis" as the US, but it faces a fragmentation crisis. Governance requires building massive, unwieldy coalitions of 10, 12, or even 15 different parties to pass a budget.

This dynamic often pushes the executive branch to embrace a "buy all sides" strategy, where the presidency distributes ministries and budget amendments to potentially corrupt small parties just to ensure a governing majority. This doesn't necessarily reduce ideological polarization; it just masks it behind transactional horse-trading. However, unlike the US, political violence in Brazil has historically been contained by the fact that no single side feels completely disenfranchised, because everyone has some representation at the table.

Does a Multiparty System Mean Less Hate?

The assumption is often that Proportional Representation reduces polarization because it creates a "big tent" legislature where you must negotiate. Looking at the data in 2026, this is only half true. Brazil’s system reduces affective polarization—the personal hatred of the political opposition—simply because the opposition is not a monolithic "Evil Other" but a collection of fractious, often incompetent smaller parties.

However, Brazil struggles with policy extremism. Because the electoral threshold to enter congress is low, radical parties on both the left and right can gain a foothold without needing to moderate their message to appeal to a broad 51% majority. They only need a dedicated sliver of the electorate. This can lead to legislative noise and the normalization of extreme viewpoints that would be filtered out in a US-style primary.

In the US, the two parties act as massive umbrellas that must suppress internal dissent to present a unified front in the general election. This suppression creates high-pressure tension that occasionally explodes, as seen in the disputes over how the president can actually use the military for domestic border control. In Brazil, the pressure is released constantly through the bickering of a dozen small parties, preventing a total build-up of pressure, but making efficient governance nearly impossible.

The Primary Problem: Where Extremism is Born

When analyzing which system reduces polarization, we must look at the mechanism that selects the candidates. In the US, the "Primary Filter" is the culprit. Since districts are non-competitive in the general election, the primary is the only event that matters. This selects for purity. Candidates who show a willingness to compromise are purged.

Brazil’s open-list system operates differently. Voters vote for a specific individual within a party list, but the party’s total vote count determines how many of their candidates get elected. This creates intra-party competition. A candidate from the same party is your direct rival for the seat. This forces Brazilian politicians to focus intensely on personal service to their local constituents—bringing home federal pork for their specific municipality—to get elected. While this breeds corruption (the "budget amendment" scams), it also forces politicians to be responsive to local needs rather than rigid national ideologies.

In the US, a representative can ignore their district's local economic needs to vote strictly along party lines on national culture war issues and still get re-elected, because the primary electorate rewards ideological loyalty. The Brazilian politician ignores their local base at their peril, regardless of their party’s national stance.

The Verdict on Gridlock

If the definition of polarization is "legislative gridlock caused by partisan animosity," the Proportional Representation model employed by Brazil performs better than the US District system. This may sound counterintuitive given Brazil’s messy politics. However, Brazil always gets a budget passed. Brazil always forms a government. The system forces cooperation because no one can govern alone.

The United States, conversely, is currently facing the prospect of a fourth consecutive continuing resolution to keep the government open, with Speaker elections dragging on for days as a small faction of the majority party holds the entire country hostage. The US system creates a situation where one party can control the entire agenda without needing a single vote from the opposition, fostering a "scorched earth" policy when power changes hands.

The Recommendation: Mixed-Member Proportional

So, which reduces polarization? The answer is not a pure adoption of the Brazilian model, which has its own demons of fragmentation and corruption. The solution for the United States—and the lesson for Brazil—is a Mixed-Member Proportional (MMP) system.

I recommend a system where 50% of the legislature is elected by local districts (preserving the tie between a representative and their community) and 50% is elected from a party list to ensure the overall parliament reflects the popular vote. This breaks the duopoly.

If the US adopted MMP, a Republican in a deep-blue state or a Democrat in a deep-red state would still have a reason to vote. Their vote would count toward the party list, ensuring their voice is represented in Congress even if they lose their local district. This lowers the stakes of every single election. When the stakes are lower, the temperature goes down.

For Brazil, the recommendation is the inverse: raise the electoral threshold. Brazil requires parties to clear a very low hurdle to enter congress. Raising this threshold would force smaller parties to merge into larger coalitions, creating actual blocs that can negotiate, rather than a chaotic free-for-all of 30 parties selling votes to the highest bidder.

Beyond the Ballot Box

Changing the math of elections is not a panacea. We saw in how the online disinformation bill passes in 3 stages that media ecosystems drive polarization just as much as district maps. If we fix the districts but leave the algorithmic outrage machines unchecked, the hatred will persist.

However, the US single-member district system acts as an accelerant. It takes the sparks of cultural conflict and pours gasoline on them by structuring politics as a zero-sum game where one side’s total victory is the only acceptable outcome. Brazil’s proportional system is a messy, imperfect bazaar, but a bazaar is preferable to a duel. In a duel, someone dies; in a bazaar, you might get haggled down, but the market continues to function.

Ultimately, the US must abandon the winner-take-all fetish if it wants to break the fever. The Brazil model proves that while proportional systems are noisy, they are rarely suicidal. The US model, left unchecked, risks becoming exactly that.