Thus, we have two rounds of voting: once to choose a leader, and a second time to vote on a leader’s proposal. The key insight is that the quorums for those two votes must overlap: if a vote on a proposal succeeds, at least one of the nodes that voted for it must have also participated in the most recent leader election [105]. Thus, if the vote on a proposal does not reveal any higher-numbered epoch, the current leader can conclude that no leader election with a higher epoch number has happened, and therefore be sure that it still holds the leadership. It can then safely decide the proposed
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