Types of Electoral Systems

Why This Matters

Electoral systems are the rules that translate votes into political power—and those rules have profound consequences for everything you'll study in comparative politics. The choice between different systems shapes party systems, coalition formation, representation of minorities, government stability, and even voter behavior. When you see a country with dozens of parties in parliament versus one dominated by two major parties, the electoral system is almost always a key explanation.

You're being tested on your ability to analyze how institutional design creates political outcomes. Don't just memorize which countries use which systems—understand the mechanisms behind them. Why does First-Past-the-Post tend to produce two-party systems? Why does Proportional Representation lead to coalition governments? These cause-and-effect relationships are what FRQs will ask you to explain. Know what Duverger's Law predicts, understand the tradeoffs between representation and accountability, and you'll be ready for whatever the exam throws at you.

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Majoritarian Systems: Winner-Takes-All Logic

These systems prioritize clear winners and government accountability over proportional representation. The underlying mechanism is simple: whoever gets the most votes wins, even without a majority. This creates strong incentives for voters to consolidate around viable candidates and for parties to build broad coalitions before elections rather than after.

First-Past-the-Post (FPTP)

• Single-member districts with plurality rule—the candidate with the most votes wins, no majority required
• Duverger's Law in action: strategic voting and wasted votes push systems toward two dominant parties over time
• Used in the UK, US, and India—produces clear government mandates but can create significant gaps between vote share and seat share

Two-Round System

• Majority requirement triggers runoff elections—if no candidate wins 50%+ in round one, top candidates face off in round two
• Encourages coalition-building between rounds as eliminated candidates endorse remaining contenders
• Common in French presidential elections—ensures winners have broader legitimacy than simple plurality systems

Block Voting

• Multiple votes in multi-member districts—voters cast as many votes as there are seats available
• Amplifies majoritarian effects because dominant parties can sweep all seats in a district
• Risks diluting minority representation—even substantial minority groups may win zero seats if votes are dispersed

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Proportional Systems: Seats Match Votes

Proportional Representation (PR) systems aim to make legislatures mirror the electorate. The core mechanism allocates seats based on vote share, so a party winning 30% of votes gets roughly 30% of seats. This dramatically lowers the threshold for representation and encourages multi-party systems.

Party-List Proportional Representation

• Voters choose parties, not individual candidates—seats distributed according to each party's vote percentage
• Closed vs. open lists matter: closed lists give party leaders control over who enters parliament; open lists let voters influence candidate ranking
• Produces coalition governments because single-party majorities are rare—seen in Israel, Netherlands, and Brazil

Single Transferable Vote (STV)

• Ranked-choice voting in multi-member districts—voters order candidates by preference (1st, 2nd, 3rd, etc.)
• Quota system with vote transfers: once a candidate reaches the threshold, surplus votes transfer to next preferences
• Balances proportionality with candidate choice—used in Ireland and Australian Senate elections

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Mixed Systems: Seeking the Best of Both Worlds

Mixed systems attempt to combine majoritarian accountability with proportional fairness. The mechanism typically gives voters two votes: one for a local representative (majoritarian) and one for a party (proportional). The balance between these components varies significantly.

Mixed Electoral Systems

• Dual ballot structure—voters cast one vote for a district candidate (FPTP) and one for a party list (PR)
• Compensatory vs. parallel designs: compensatory systems (Germany) use PR seats to correct disproportionality; parallel systems (Japan) keep the two tiers separate
• Germany's Mixed-Member Proportional (MMP) is the classic example—local representation plus overall proportionality

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Preferential Voting: Rankings Over Single Choices

These systems let voters express nuanced preferences rather than choosing just one candidate. The mechanism uses ranked ballots and eliminates candidates sequentially or assigns points based on ranking position. This reduces wasted votes and can produce consensus winners.

Alternative Vote (AV) / Instant Runoff Voting (IRV)

• Ranked ballots with sequential elimination—lowest-ranked candidate is eliminated and their votes redistributed until someone reaches 50%
• Reduces vote-splitting problem because supporters of similar candidates can rank them 1-2 without "wasting" their vote
• Used in Australian House elections—maintains single-member districts while ensuring majority winners

Borda Count

• Points-based ranking system—candidates receive points based on ballot position (e.g., 1st place = 5 points, 2nd = 4 points)
• Favors consensus candidates who are broadly acceptable rather than intensely preferred by a plurality
• Vulnerable to strategic voting—voters may rank strong competitors last regardless of true preferences

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Semi-Proportional Systems: Partial Solutions

These systems fall between majoritarian and proportional extremes, producing some proportionality without full PR mechanisms. They often create strategic dilemmas for parties and voters that can fragment or consolidate party systems unpredictably.

Single Non-Transferable Vote (SNTV)

• One vote per person in multi-member districts—top vote-getters win seats, but votes don't transfer
• Creates intra-party competition because parties must carefully manage how many candidates to run and how to distribute supporter votes
• Historically used in Japan and Taiwan—can produce either fragmentation or factional politics within dominant parties

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Quick Reference Table

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Self-Check Questions

1. Which two systems both use ranked ballots but produce different types of winners—and what explains the difference in outcomes?

2. A country wants to maintain local district representation while ensuring overall proportionality in parliament. Which system should they adopt, and how does its mechanism achieve both goals?

3. Compare FPTP and Party-List PR: How does each system affect the number of parties, the likelihood of coalition governments, and the representation of minority viewpoints?

4. Why might SNTV create strategic dilemmas for political parties that FPTP does not? What must parties calculate when deciding how many candidates to nominate?

5. If an FRQ asks you to explain why France uses a Two-Round System for presidential elections rather than FPTP, what argument about democratic legitimacy should you make?