Two-round voting, also called the Two-Round System or TRS, is a plurality or majority electoral system in which an initial election is followed by a second election if no candidate or party reaches the threshold required to win in the first round. International IDEA defines the Two-Round System as a system in which a second election is held if no candidate or party achieves a specified level of votes, most commonly an absolute majority.
The second round can operate in different ways. Under a majority run-off system, normally only the two leading candidates from the first round compete in the second round. Under a majority-plurality version, more than two candidates may proceed and the candidate with the highest vote total in the second round wins even without an absolute majority. The essential feature is therefore the use of separate election rounds rather than a single ballot with transferable preferences.
In a conventional majority runoff, the first round allows voters to choose among several candidates. If one candidate obtains the required absolute majority, that candidate wins immediately and the second round is unnecessary. If no candidate reaches the threshold, the leading candidates proceed to a second ballot. Voters then make a new choice in light of the first-round results. The second round is therefore a separate election, not merely another counting stage of the original ballots.
Parties and candidates that did not qualify can potentially support or negotiate with remaining candidates, while voters can reconsider their preferences. This creates a different political environment in the second round because the field is narrower and the likely consequences of each vote are clearer. The precise qualification rules, timing between rounds and threshold for winning vary by jurisdiction.
Two-round voting differs fundamentally from the alternative vote even though both can produce a majority winner. In AV, voters rank candidates on one ballot and later preferences are transferred automatically when candidates are eliminated. In a two-round system, voters normally cast a new ballot in the second round. They can therefore reconsider their choice after observing first-round results, candidate withdrawals, endorsements or political negotiations. The two mechanisms use different information structures.
AV records several preferences before the voter knows which candidates will survive, while TRS allows the voter to make a later decision after the first contest has occurred. International IDEA classifies AV and TRS separately within the plurality and majority family. The distinction is therefore not simply terminology but concerns whether the runoff is created through vote transfers or through a genuinely separate election.
The threshold determining whether a second round occurs is a crucial design element. The most common trigger is failure to obtain more than half of the valid votes in the first round, but some electoral laws use other thresholds or qualification rules. A system may permit the top two candidates to advance, which guarantees a two-candidate second round, or it may permit several candidates to advance if they satisfy a specified percentage.
The majority-plurality variant allows the candidate with the highest second-round vote total to win even if that candidate does not exceed half of the votes. These distinctions affect the number of candidates who remain viable, the incentives for alliances and the relationship between first-round support and final victory. Consequently, the phrase two-round system does not itself determine the exact runoff rule.
Two-round elections can produce a sequence of political competition in which the first and second rounds perform different functions. The first round can allow voters to express a relatively broad preference among multiple parties or candidates. The second round narrows the field and forces a more concentrated choice. Candidates who fail to qualify may endorse another candidate, while voters who supported eliminated candidates must decide whether to support a remaining candidate, abstain or cast a protest or other permitted ballot.
This can encourage alliances between political groups between rounds. It can also change campaign messages because candidates need to appeal to a broader electorate in the final contest. These effects depend heavily on the number of candidates, party system, qualification rules, timing and whether voting occurs simultaneously across all districts or through other arrangements.
Two-round systems are used in a variety of electoral contexts, including presidential elections and legislative elections. International IDEA identifies France and Mali among examples of jurisdictions using two-round arrangements in its comparative material, while its current database classifies numerous countries under TRS. The system can also be applied differently to different offices within the same country. A presidential election may use a majority runoff while legislative elections use another electoral method.
The term therefore describes an election mechanism rather than an entire constitutional system. In some countries, legislative districts use two rounds for individual representatives, while in others the system is reserved for executive offices. The precise legal rules determine who advances, what threshold applies and whether the second round is a majority runoff or a majority-plurality contest.
The two-round system can be understood as a method of separating broad first-round competition from concentrated final selection. Its first round permits multiple candidates to compete, while the second round provides another opportunity to select among those who remain. This differs from first-past-the-post, where the highest first-round total is immediately sufficient, and from AV, where later preferences are already encoded on the original ballot.
It also differs from STV because it normally elects one candidate in a district rather than allocating several seats proportionally through transfers. Two-round voting therefore belongs to the plurality or majority family rather than the proportional representation family. Its defining feature is not simply that an election has two stages but that the second stage is a distinct ballot triggered by the failure to satisfy a specified first-round condition.
Two-round voting is therefore a plurality or majority electoral system using a separate second election when the first round does not produce a result satisfying the specified winning or qualification threshold. The common majority-runoff version advances the leading candidates to a second ballot, while other versions permit a wider field and determine the winner by plurality in the second round.
The system differs from alternative vote because the second decision is made by voters through a new ballot rather than through automatic transfer of preferences, and it differs from STV because it normally concerns a single winner rather than proportional multi-member representation. The practical effects depend on qualification rules, turnout, candidate withdrawals, alliances, timing and the precise second-round formula.
