Countries engaged in transitions from Communist rule to democracy and market economies face a considerable challenge to foster tax morale and to reduce tax evasion. Tax evasion, however, severely limits the capacities of these reformed states, which reduces in a vicious circle the citizens' incentives to pay taxes. The question then arises how this vicious circle may be broken. Several authors suggest that political institutions may do the trick. Based on insights that institutions allowing a direct say on policy issues (especially tax questions) may increase tax morale, we propose to study comparatively how the link between trust and tax morale is affected by these institutions. We find that allowing for referendums strengthens the link between trust and tax morale, but that this effect depends on the nature of the institutions.