Leaderless protocols exist in the literature (EPaxos, Caesar, Tempo, ...). These systems usually have a "leader" per transaction, but the leader role is unconte

Leaderless protocols exist in the literature (EPaxos, Caesar, Tempo, ...). These systems usually have a "leader" per transaction, but the leader role is uncontested in normal operation, as it is self-declared by the coordinator of the transaction, so an election only takes place if the coordinator of that transaction fails for whatever reason. Multiple leaders may exist concurrently for any given datum/key the operation involves. Cassandra is currently developing a leaderless protocol in this vein called Accord. In fact, Cassandra is already using a leaderless protocol for its LWTs; an optimised variant of classic (single-decree) Paxos, but this has significant overheads when competing transactions are declared for the same key at the same time.