Electoral Systems Compared: FPTP, Proportional Representation, and Mixed Systems

The Simplest Rule in Democracy#

First-past-the-post (FPTP), also called plurality voting or single-member district plurality, is the oldest and simplest electoral system. Voters in a geographic constituency (or "riding", "district", "seat") cast one vote for one candidate. Whoever receives the most votes wins the seat — even if that is not a majority. The party that wins the most seats nationally typically forms the government.

FPTP is used for lower-house elections in the United Kingdom, United States, Canada, India (the world's largest FPTP election by a huge margin), Bangladesh, and several African and Caribbean countries that inherited the Westminster tradition. It is not used for the lower house of any continental European democracy.

How Votes Translate Into Seats#

Supporters of FPTP argue it creates clear winners, direct MP-constituent links, and strong single-party governments that can be held accountable at the next election. A UK voter can walk into their local constituency office and speak to "their" MP; a U.S. voter similarly knows exactly who represents them in Congress.

Critics focus on disproportionality. Because only one candidate per district wins, votes for losing candidates are — in a strict sense — wasted. In the 2019 UK general election, the Conservative Party won 43.6% of the popular vote but 56.2% of the seats; the Liberal Democrats won 11.5% of the vote but 1.7% of the seats. In the 2015 UK general election, UKIP received 3.8 million votes (12.6%) but won exactly one seat.

Example: In Canada's 2019 federal election, the Liberal Party formed a minority government despite winning fewer votes than the Conservatives — because Liberal support was more efficiently distributed across constituencies. FPTP rewards geographically concentrated support and punishes geographically dispersed support.

Safe Seats and Swing Seats#

Under FPTP, most constituencies are safe seats where one party reliably wins by a wide margin. Election campaigns concentrate on a small number of swing seats or "marginals". In U.S. presidential elections, where the Electoral College layers a FPTP-style rule on top of state-by-state voting, campaigns focus on six or seven "swing states" while ignoring most of the country.

This creates a policy consequence: parties tailor their platforms to median voters in marginal constituencies, not to the median voter nationally. In the UK, political scientists have documented that policy in areas like pensions, housing, and northern economic development has been shaped by the preferences of a few dozen swing seats.

Strategic Voting#

FPTP also incentivises strategic voting. Supporters of a smaller party may vote for their second-choice major party to keep a third party out. British Liberal Democrat and Green voters frequently vote Labour or Conservative strategically; Canadian NDP voters may vote Liberal to block the Conservatives. Indian voters often engage in elaborate local coalition-building to concentrate anti-incumbent votes.

Political scientists call this pattern Duverger's Law: plurality voting tends to produce two dominant parties. The theoretical logic is that voters learn to avoid "wasting" their vote on candidates who cannot win. Duverger's law is a tendency, not an iron rule — the UK, Canada, and India all have significant third parties — but the two-party pattern is unmistakable in FPTP systems.