Parallel Voting - Advantages and Disadvantages

Advantages and Disadvantages

SM allows smaller parties that cannot win individual elections to secure some representation in the legislature; however, unlike in a proportional system they will have a substantially smaller delegation than their share of the total vote. It is also argued that SM does not lead to the degree of fragmentation found in party systems under pure forms of PR.

A criticism of proportional voting systems is that the largest parties need to rely on the support of smaller ones in order to form a government. However, smaller parties are still disadvantaged as the larger parties still predominate. In countries where there is one dominant party and a divided opposition, the proportional seats may be essential for allowing an effective opposition.

Because the vote is split between constituencies and a list, there is a chance that two classes of representatives will emerge under a SM system: with one class beholden to their electorate seat, and the other concerned only with their party. The major critique of parallel systems is that they cannot guarantee overall proportionality, small parties may still be shut out of representation despite winning a substantial portion of the overall vote.

A party that can gerrymander local districts can win more than its share of seats. So parallel systems need fair criteria to draw district boundaries. (Under Mixed member proportional representation a gerrymander can help a local candidate, but it cannot raise a major party’s share of seats.)

Countries like Japan, Russia, and Thailand adopted a parallel system as a means by which incentives for greater party cohesiveness could be injected. The party is sure to elect the candidates at the top of its list, guaranteeing safe seats for the leadership. By contrast, under the MMP system a party that does well in the local seats will not need or receive any compensatory list seats, so the leadership has to run in the local seats.