Leader election needs a majority
Majority quorum is what forbids a split brain. When the cluster is partitioned, the side with fewer than half the nodes cannot form a quorum or stay authoritative. One leader, many votes A replicated system that must not diverge elects a single leader for a term. A candidate asks peers for a vote, and to become leader it needs a quorum, more than half of the voting members in a fault-tolerant scheme, to say yes within a term. That majority is what lets the winner act with confidence that no split-off minority can out-vote it, so the group can make decisions with one authority at a time. Exactly half is not enough: quorums are defined as strictly more than half, which is what makes two halves never both be authoritative. ...