Two node / even node clusters can work fine. For even n>2 you define a tie breaker node in advance and only the partition connected to that node can make a quo

Two node / even node clusters can work fine. For even n>2 you define a tie breaker node in advance and only the partition connected to that node can make a quorum at 50%. For n=2 going from no quorum to quorum requires both nodes but losing a node doesn't lose quorum, and when you lose a node you stop, shoot the other node, and continue. For split brain the fastest draw wins the shootout.