Plurality — Choose-One / First-Past-The-Post¶
The status quo for most US single-winner elections, and the baseline every reform on this site improves on. Mark exactly one candidate; whoever gets the most marks wins — even without a majority. Simple to count, but it forces the problems the other methods are designed to fix.
→ The problems it creates: the spoiler effect · vote splitting & the equally-weighted vote · is IRV just plurality in sequence? RCV-IRV and plurality
How it works¶
Each voter marks one candidate. Add up the marks. The candidate with the most marks wins — a plurality, which need not be a majority. That's the whole method. Its other names: Choose-One, First-Past-The-Post (FPTP), single-mark, first-preference plurality (FPP).
What's wrong with it¶
The single mark is the root of a whole family of problems:
- Vote splitting & spoilers. Similar candidates divide their shared supporters, so a less-preferred candidate can win with a minority. A candidate who can't win still changes who does — the spoiler effect. Plurality is the method most susceptible to it.
- Minority winners. With three or more candidates, the winner routinely has less than half the vote — a plurality/minority winner a majority actively voted against. "Routinely" is measurable: 11.9% of all 5,662 US national primaries in 2022 had multiple candidates and a sub-majority winner (how to read that number honestly).
- Lesser-evil voting & favorite betrayal. Because backing your true favorite can "waste" your vote or help your worst choice, voters are pressured to abandon their favorite for a viable front-runner — the favorite-betrayal incentive.
- No expression. One mark captures neither order (who's your second choice?) nor strength (how much do you like them?) — see ballot styles.
- Two-party entrenchment. These pressures push the field toward two viable candidates over time (Duverger's law).
Show me — a minority winner, worked¶
100 voters, three candidates. Under Choose-One only first choices count:
| Candidate | First choices | |
|---|---|---|
| Ada | 34 — 34% | ← wins |
| Ben | 33 | |
| Cleo | 33 |
Ada takes office on 34% — but 66 of the 100 voters scored her 0 or 1. Two-thirds didn't want her; they just split their first choices between Ben and Cleo. Now read the whole ballot: Cleo is nobody's fiery favorite (33 first choices) but everybody's easy second — she leads STAR's scoring round (433), wins the automatic runoff over Ada 66–34, and beats both rivals head-to-head (the Condorcet winner). STAR and Ranked Robin both elect Cleo, the candidate a majority is genuinely glad about; only first-choice counting crowns Ada. Same opinions, no strategy — the difference is how much of the ballot the method reads. (With a bigger field it gets starker — Choose-One winners can take office on 10–20%.) ▶ See it live on BetterVoting (all three counts). The full worked page: minority winner · the whole field lined up: same opinions, every method.
This isn't hypothetical — it's North Carolina. A NC primary can be won with just over 30% of the vote (the threshold was cut 50% → 40% → 30% to make runoffs rarer); below it, the runner-up may request a separate, low-turnout "second primary." The general election has no minimum at all — the most votes wins, even far below a majority, so a candidate most voters ranked low can still take office. STAR's fix uses the same ballot with an automatic runoff built in: a majority-backed winner and no costly second trip to the polls. (NC's ranked-ballot history: RCV-IRV in North Carolina.)
Its relationship to the other methods¶
Every method this library teaches is, in part, a fix for one of plurality's failures:
| Reform | What it changes about the single mark |
|---|---|
| Approval | Mark as many candidates as you like — similar candidates stop splitting. |
| RCV-IRV | Rank candidates; eliminate-and-transfer instead of one round. (In fact plurality is just IRV with a ranking limit of 1 — see RCV-IRV and plurality.) |
| Ranked Robin | Rank, then compare every pair head-to-head — elects the majority-preferred candidate. |
| Score / Range · STAR | Rate each candidate 0–5 — captures order and strength; STAR adds a runoff. |
Where it's used¶
Most US single-winner offices — Congress (in most states), governorships, state legislatures, and the plurality stage of countless local races — still use plurality, which is why the spoiler and vote-splitting stories in this library are not abstract.
Sources: Plurality voting — Wikipedia, First-past-the-post voting — Wikipedia, Duverger's law — Wikipedia