Supporters of President Yoon Suk Yeol hold a rally in front of the presidential residence in Hannam-dong, central Seoul, Jan. 13, ahead of his detention over his Dec. 3 martial law declaration. Korea Times photo by Shim Hyun-chul

The ideological divide in Korea has deepened, fueled by the political turmoil caused by President Yoon Suk Yeol's Dec. 3 declaration of martial law last year.

The two major political parties are seeing increased support while the number of undecided voters is shrinking. A survey on public perceptions concerning social divisions among Koreans shows that ideological conflict is seen as the most pressing issue, surpassing concerns like gender and wealth inequality.

In Gallup Korea's latest poll, the ruling People Power Party (PPP) received 38 percent support, while the main opposition Democratic Party of Korea (DPK) garnered 40 percent. Both figures surpass the average annual support rate for the two main rival parties, which was at 32 percent last year.

Gallup Korea surveyed 1,000 adults in phone interviews from Jan. 21 to 23. The poll has a margin of error of plus or minus 3.1 percentage points, with a credibility rate of 95 percent. Further details are available on the National Election Survey Deliberation Commission's website.

By political inclination, 77 percent of respondents who consider themselves conservative said they support the PPP while 79 percent of those who claim to be liberal support the DPK.

In mid-December last year, following the opposition-controlled National Assembly's passage of a motion to impeach Yoon over his martial law declaration, the DPK's support surged to a record high of 48 percent — the highest since the current administration took office. This widened the gap with the PPP, which stood at 24 percent.

However, only the two main rival parties have seen their support rates remain neck-and-neck amid the political turmoil, while support for minor parties has dwindled.

The percentage of undecided voters — those who have not yet decided or refuse to support a party — dropped from 19 percent to 17 percent between the second and third week of January, and then fell further to 15 percent the following week, according to the poll.

The figure is much lower than last year's average of 23 percent and is close to the 14 percent seen in the first week of March 2022, just before the presidential election.

In addition, a recent survey shows that the majority of Koreans consider the ideological divide between conservatives and liberals to be the country's most pressing social issue.

According to the "2024 Public Conflict Awareness Survey of Koreans" by the Korea Social Conflict Resolution Center and Korea Research, 91.3 percent of the 1,000 respondents aged 19 and over said that the ideological divide between liberals and conservatives is the most pressing issue, far surpassing 13 other types of conflicts, including those between the rich and poor, labor and management, as well as regional and gender divides.

As a result, the proportion of Koreans citing the ideological divide as the most pressing concern surpassed 90 percent for the first time in 2024, after staying at around 80 percent since the annual survey started in 2013.

Driven by tensions between the two main rival parties during the impeachment process, regionalism intensified to 66.8 percent last year, up by 8.1 percentage points from 58.7 percent in 2023, the survey showed.

Citizens stage a sit-in protest in central Seoul, Jan. 6, demanding President Yoon Suk Yeol's resignation over his martial law declaration. Korea Times photo by Choi Won-suk

Korea's decades-old regional divide — between the southwestern and southeastern regions — is evident in voting trends, with conservatives holding strong in the southeastern region, including Daegu and the Gyeongsang provinces, while liberals dominate the southwestern region, including Gwangju and the Jeolla provinces.

"Before the emergency martial law declaration, the crisis of declining provincial economies was more pressing than the political divide in how Koreans perceived regional conflicts. However, as the conflict between political parties intensified during the impeachment process, it began to significantly influence the public's perception of the political leanings of the regions," said Lee Kang-won, director of the Korea Social Conflict Resolution Center.

The nation's ideological rift deepened due to increasing political intolerance, data shows.

According to the Manifesto Project at the Social Science Research Center in Berlin, Germany, Korea's ideological polarization index increased from 0.36 in 2012 to 1.26 in 2020, reflecting a significant widening of the political divide between the two major parties and voters over the past decade. And the latest crisis has only worsened the situation.

The Manifesto Project collects and analyzes political party platforms and voter turnout data from around the world, publishing an annual ideological polarization index. A higher index indicates greater polarization.

Korea's leading public policy think tank shares a similar view.

In a seminar on political polarization in Asia held by the East Asia Institute and the Asia Democracy Research Network on April 6, 2022, the group said Korea's political polarization index was 2.69 in 2021, ranking 11th among 38 OECD countries. This figure was notably higher than the OECD countries' median value of 2.07.

Experts warn that Korea is possibly on the verge of destructive polarization, which could pose a grave challenge to democracy.

"Political polarization simplifies politics by presenting either-or choices to the public. It usually has a detrimental impact on democracy as it divides the electorate into two mutually mistrustful camps," said Lee Sook-jong, a professor of Public Administration at Sungkyunkwan University who participated in the seminar as a panelist.

"When the public is divided into 'us and them' and develops antipathy or even hatred toward each other, mutual tolerance and institutional forbearance are at risk," she said.