[News Terms] Parallel vs. Mixed-Member... What’s the Difference in the 'Proportional Representation System'?

As the 22nd general election scheduled for April 10 next year approaches, discussions on electoral system reform are heating up in the political arena. In particular, both ruling and opposition parties are busy calculating whether to revert to the parallel voting system maintained until the 20th National Assembly, maintain the semi-proportional representation system applied in the 21st National Assembly, or introduce a regional proportional representation system regarding proportional representation seats.

On the 10th, at the National Assembly, Cho Eung-cheon (second from the left in the front row), Yoon Young-chan, Lee Won-wook, Kim Jong-min, and other members of the Democratic Party's non-mainstream group "Principles and Common Sense" held signs reading "Withdraw the Satellite Party Trick!" and shouted slogans with the attendees during the talk show "Together with the People." [Image source=Yonhap News]

Proportional representation is an electoral system that determines the number of elected candidates in proportion to the total votes received by political parties. Currently, South Korea's National Assembly consists of 300 members, divided into 253 constituency members and 47 proportional representation members.

Among these, the 'parallel voting proportional representation system' is a method where constituency members and proportional representation members are elected separately through different votes. Voters cast one vote for their preferred candidate running in their constituency and one vote for a party in the proportional representation ballot. Because the results of the constituency and proportional representation votes do not affect each other, it is called 'parallel.' The 253 constituency seats are won by the candidates who receive the most votes in each district, while the 47 proportional representation seats are distributed among parties based on their share of the party vote. This voting system is simple and easy for voters to understand, but a downside is that the two major parties can dominate not only the constituency seats but also most of the proportional seats.

On the other hand, the 'mixed-member proportional or semi-proportional representation system' links the number of constituency seats to the party vote share. Ahead of the 21st general election, the Democratic Party, in coalition with other minor parties, passed this 'semi-proportional representation system.' The mixed-member proportional system fills 100% of the shortfall in seats if the number of constituency seats is less than the party's nationwide vote share, while the semi-proportional system fills about 50% of the shortfall. This means that the more constituency seats a party wins, the fewer proportional seats it receives. Since it is difficult for minor parties to win constituency seats, this system allows them to gain more proportional seats, ensuring their voices are better represented in the National Assembly. However, this system is disadvantageous to the two major parties, which need to secure even one more seat to win the election. Consequently, there is a possibility of satellite parties exploiting proportional seats, leading to fierce debates over institutional reforms to ban such practices in recent electoral reform discussions.

The 'regional proportional representation system' divides the country into several regions and elects proportional representatives based on party support rates within each region. Elected candidates are determined according to the order of the regional proportional representation lists submitted by each party in advance. This system has the advantage of alleviating the chronic problem of regionalism in domestic politics and supplementing regional representation. For example, if Yeongnam and Honam are each grouped into one region, Democratic Party members could be elected from the Daegu-Gyeongbuk area, and People Power Party members from Honam. However, a drawback of introducing the regional proportional representation system is that candidates must be from the respective region, which may narrow the pool of talent available.

In recent electoral reform discussions, the People Power Party has early on settled on the parallel voting proportional representation system and advocates a return to the previous electoral system. Meanwhile, within the Democratic Party, there are opinions to return to the parallel system but introduce the regional proportional representation system.