Electoral systems have long been considered to have specific effects on issues of governance, policy making and political stability. Different electoral systems have marked implications for governance in parliamentary systems. In particular, there is an inbuilt tension between electoral systems which maximize the potential for one-party government (e.g. plurality/majority systems) and those which make multiparty coalitions more likely (e.g. proportional systems). Both constellations have clear policy impacts: single-party government makes decisive policy making and clarity of responsibility much easier, while coalitions are more likely to produce more representative policies and more inclusive decision making. Similarly, major shifts in government policy are easier to achieve under single-party government, while coalitions are more likely to see issues discussed and debated before any changes are made.
Almost all countries which have a presidential or semi-presidential constitution elect the president directly. In addition, some republics which have parliamentary constitutions nevertheless elect their head of state directly. In presidential systems, the extent to which an elected president can claim a popular mandate and legitimacy depends significantly on the means by which he or she is elected. Presidents who have clear majority support are likely to have much greater legitimacy and be in a stronger position to push their own policy agenda than those elected on a small plurality of the vote. This has an important impact on relations between the president and the legislature. A president elected by a clear absolute majority of the population can command a great deal of legitimacy in any conflict with the legislature. By contrast, Salvador Allende’s election in Chile in 1970 on 36 per cent of the vote, and opposed by a right-wing Congress, helped create the conditions for the 1973 military coup.
The relationship between the legislature and the executive differs between parliamentary, semi-presidential, and presidential systems. In a presidential or semi-presidential system, the president’s position does not depend on maintaining the confidence of the legislature: such a president cannot be removed from office on purely policy grounds. However, experience in Latin America in particular indicates that a directly elected president without a substantial block of support in the legislature will find successful government difficult. In presidential and semi-presidential democracies, the electoral systems for the presidency and the legislature therefore need to be considered together, although the different roles of the president and the legislature bring different factors into play in making the two choices of system. The synchronization or otherwise of the presidential and legislative elections and the provisions which may encourage or discourage fragmentation of parties and the relationship between parties and elected members should be considered at the same time.
