By The South Asia Times

SEOUL– South Korean President Lee Jae-myung on Monday explained the mechanics and significance of the preferential voting system, stating that it was introduced alongside the runoff voting system during his tenure as the leader of the Democratic Party.

Writing on his X social media account, Lee detailed how the system works to eliminate the need for a separate runoff election.

"When the first-place candidate in the primary vote fails to secure a majority, this system allows for a preliminary runoff vote to be conducted in advance during the primary vote, eliminating the need for an additional runoff," Lee said.

According to Lee's explanation, in a three-way contest, voters are asked to mark both their first and second preferences on the ballot. If no candidate secures a majority, the second-choice votes from supporters of the third-place candidate are added to the first- and second-place candidates -- producing the same effect as a runoff without holding a separate election.

"The preferential voting system is designed to save on the costs and time of a runoff," Lee noted, though he acknowledged a limitation: it assumes that voters who selected first and second preferences in the primary would make the same choices in an actual runoff.

He also warned voters that failing to select a second preference would effectively mean abstaining in a runoff where their first-choice candidate is eliminated.

The preferential voting system is currently being used in the Democratic Party's primary to elect the next National Assembly Speaker. According to reports, the primary involves three candidates: Park Ji-won, Cho Jung-sik, and Kim Tae-nyeon.

Party members with voting rights are casting ballots through an online voting system on May 11 and 12, with results counting for 20 percent of the final tally. National Assembly members' votes will account for the remaining 80 percent.

Under the preferential voting system, voters rank candidates from 1 to 3 in order of preference. If no candidate receives more than 50 percent of the votes, the top two candidates immediately proceed to a final round, with preference rankings ensuring that party members' intentions are meaningfully reflected.

The preferential voting system -- known internationally as "instant-runoff voting" or the "alternative vote" -- allows voters to rank candidates in order of preference on a single ballot. If no candidate receives an absolute majority of first-preference votes, the lowest-placed candidate is eliminated, and their votes are redistributed to the remaining candidates according to voters' stated preferences. This process continues until one candidate achieves a majority.

Cost and Time Savings: By merging two rounds of voting into one, the system eliminates the need for expensive and logistically challenging runoff elections. This was a primary motivation for its adoption in party primaries.

Majority Mandate: The system ensures that winning candidates have the support of more than 50 percent of voters—either through first preferences or through transferred preferences—rather than winning with only a plurality.

Reduced Tactical Voting: Voters can support smaller or less competitive candidates as their first choice without "wasting" their vote, knowing their second preference will still count if their preferred candidate is eliminated.

Positive Campaigning: Candidates have incentives to appeal for second- and third-preference votes, encouraging more issue-oriented and less negative campaigning.

- Limitations

Complexity: Voters must understand how to rank candidates, which can be challenging for some, particularly those with lower literacy levels or first-time voters. Informal ballot rates tend to be higher under preferential systems.

Assumption of Consistent Preferences: As Lee noted, the system assumes voters' preferences remain unchanged between rounds, which may not always hold true in a real runoff scenario.

Voter Education Required: Lee emphasized that voters must be aware that they need to select both first and second preferences to avoid disenfranchising themselves if their first-choice candidate is eliminated.

President Lee indicated that, as South Korea considers introducing runoff systems for national elections, such as the presidential race, discussions on simultaneously adopting the preferential voting system will likely follow.

"Discussions on simultaneously adopting the preferential voting system will likely follow," Lee said, pointing to broader electoral reform possibilities for the country.

The current application of the system in the Democratic Party's National Assembly Speaker primary represents a practical test case that could inform future electoral reform debates in South Korea.