Two-Round Electoral System

A two-round electoral system elects a president through an initial vote and, if necessary, a second vote between the leading candidates. In its usual presidential form, a candidate wins immediately by securing an absolute majority, meaning more than half of the votes counted for determining the result; otherwise, the two leading candidates contest a runoff.

How the winner is determined

The system combines an initially broad choice of candidates with a decisive majority contest if the first round produces no outright winner.

• In the first round, voters choose among the presidential candidates, and a candidate who crosses the prescribed majority threshold is elected without another round.
• If nobody crosses that threshold, the two highest-polling candidates normally advance to the second round, while the other candidates are eliminated.
• In the runoff, voters make a fresh choice between the finalists, and the candidate receiving more valid votes wins.
• First-round vote totals are not added to second-round totals; the runoff result determines the winner.

Understanding the majority requirement

An absolute majority differs from a plurality: a plurality means receiving more votes than any rival, even without receiving more than half. The relevant denominator is defined by electoral law, not automatically by the total number of registered voters.

• For example, if three candidates receive 42%, 35% and 23% of valid votes, none has an absolute majority, so the first two proceed to the runoff.
• If the finalists then receive 53% and 47%, the candidate with 53% wins, even if that candidate finished second in the first round.
• For Brazil's presidency, Article 77 requires an absolute majority excluding blank and invalid votes; if necessary, a second election is held between the two leading candidates.

Why the second round matters

The runoff allows voters whose preferred candidates were eliminated to choose between the finalists. Candidates may therefore seek endorsements and support beyond their original electoral base.

• Unlike first-past-the-post, the usual majority-runoff model does not elect a president merely for leading a divided first-round field.
• A runoff majority demonstrates support among votes counted in that round, not necessarily among all registered voters.
• The system may encourage coalition-building, but it also requires another election when no candidate wins outright.