Key Electoral Systems

Why This Matters

Electoral systems are the invisible architecture of democracy—they determine how millions of votes get translated into actual political power. When you're covering politics, understanding these systems isn't optional; it's the difference between explaining why a party won 40% of votes but got 60% of seats, or why some countries have two dominant parties while others have twelve. You're being tested on your ability to analyze how institutional rules shape political outcomes, from party system fragmentation to voter behavior to government stability.

The key concepts here revolve around proportionality, district magnitude, ballot structure, and strategic voting incentives. Don't just memorize which countries use which system—know what trade-offs each system creates. A question about coalition governments is really asking about proportional systems; a question about "wasted votes" is probing your understanding of winner-take-all mechanics. Master the why behind each system, and you'll be ready for anything from multiple choice to document analysis.

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Winner-Take-All Systems

These systems award seats to whoever gets the most votes in a district, creating clear winners but often leaving many voters unrepresented. The core mechanism is simple: plurality wins, proportionality loses.

First-Past-the-Post (FPTP)

• Single-member districts with plurality rule—whoever gets the most votes wins, even without a majority (35% can beat 33% and 32%)
• Duverger's Law in action: smaller parties get squeezed out because voters fear "wasting" their vote on candidates who can't win
• Vote-seat distortion is the signature problem—a party can win 40% of votes nationally but capture 60% of seats if their support is efficiently distributed

Block Voting

• Multiple votes per voter—in multi-member districts, voters cast as many votes as there are seats available
• Majoritarian sweep effect: the largest party or coalition often wins all seats in a district, amplifying their advantage
• Minority underrepresentation is a documented outcome—groups without plurality support in a district get shut out entirely

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Proportional Systems

These systems aim to match seat shares to vote shares, giving smaller parties a path to representation. The mechanism: larger, multi-member districts with mathematical formulas allocating seats based on vote percentages.

Proportional Representation (PR)

• Seat allocation mirrors vote share—a party winning 25% of votes gets approximately 25% of seats
• Multi-party systems emerge because small parties can win seats without needing plurality in any single district
• Coalition governments become common, as rarely does one party win an outright majority of seats

Party-List Proportional Representation

• Voters choose parties, not candidates—the party list determines which individuals fill the seats won
• Open vs. closed lists matter: open lists let voters influence candidate ranking; closed lists give party leadership full control
• Diversity outcomes improve under this system—parties often place women and minority candidates in winnable positions to broaden appeal

Single Transferable Vote (STV)

• Ranked-choice voting in multi-member districts—voters order candidates by preference, and a quota determines winners
• Proportional results with candidate choice—unlike party-list systems, voters pick specific people, not just parties
• Minimal wasted votes because losing candidates' votes transfer to next preferences until seats are filled

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Majority-Ensuring Systems

These systems prioritize ensuring winners have broad support, using either multiple rounds or ranked ballots to build majority coalitions. The mechanism: eliminate weaker candidates until someone crosses the 50% threshold.

Two-Round System

• Runoff requirement—if no candidate wins a majority in round one, the top two (or more) face off in round two
• Broader mandate for winners, since the eventual victor must secure majority support in the final round
• Strategic dynamics shift between rounds—eliminated parties may endorse remaining candidates, reshaping coalitions

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

• Single election, simulated runoffs—voters rank candidates, and last-place finishers are eliminated with votes redistributed until someone hits 50%
• Majority winners guaranteed without requiring voters to return for a second election
• Sincere voting encouraged because ranking a minor party first doesn't "waste" your vote—your second choice still counts if needed

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Hybrid Systems

These systems attempt to capture benefits of both winner-take-all and proportional approaches, though they vary in how well they balance the two. The mechanism: voters cast multiple ballots or seats are divided between different allocation methods.

Mixed Member Proportional (MMP)

• Two votes, one integrated outcome—voters choose a local candidate (FPTP) and a party (PR), with party seats compensating for district-level disproportionality
• Local representation preserved while overall seat distribution matches party vote shares
• Voter satisfaction tends higher because citizens get both a geographic representative and influence over national party balance

Parallel Voting

• Two systems, no integration—FPTP and PR operate side by side, but PR seats don't compensate for FPTP distortions
• Partial proportionality results—the system is more proportional than pure FPTP but less than MMP
• Disproportionality persists because large parties still benefit from their FPTP wins without losing compensatory seats

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Consensus-Building Systems

These systems prioritize finding candidates with broad acceptability rather than just plurality or majority support. The mechanism: aggregate ranked preferences to identify candidates least objectionable to the most voters.

Borda Count

• Points-based ranking—candidates receive points based on their position in each voter's ranking (e.g., 5 points for first, 4 for second, etc.)
• Consensus candidates favored because a candidate ranked second by everyone beats one ranked first by half and last by half
• Polarization reduction is a design goal—extremists who inspire strong opposition struggle to accumulate points

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Quick Reference Table

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Self-Check Questions

1. Which two systems both use ranked ballots but differ in whether they guarantee proportional representation? What explains this difference?

2. A country wants to maintain local constituency representatives while ensuring overall seat distribution matches national vote shares. Which system should they adopt, and why wouldn't Parallel Voting achieve this goal?

3. Compare FPTP and PR in terms of their effects on party system fragmentation. What mechanism in each system produces these different outcomes?

4. If an FRQ asks you to evaluate trade-offs between voter choice and party control, which two systems would provide the strongest contrast? Explain your reasoning.

5. A reformer argues that "wasted votes" undermine democratic legitimacy. Which three systems most directly address this concern, and through what different mechanisms?