A domain of preference orderings is a random dictatorship domain if every strategy- proof random social choice function satisfying unanimity dened on the domain, is a random dictatorship. Gibbard (1977) showed that the universal domain is a random dictatorship domain. We investigate the relationship between dictatorial and random dictatorship domains. We show that there exist dictatorial domains that are not ran- dom dictatorship domains. We provide stronger versions of the linked domain condition (introduced in Aswal et al. (2003)) that guarantee that a domain is a random dicta- torship domain. A key step in these arguments that is of independent interest, is a ramification result that shows that under certain assumptions, a domain that is a ran- dom dictatorship domain for two voters is also a random dictatorship domain for an arbitrary number of voters.
