[EAI Issue Brief] South Koreans' Perceptions of Bloc Formation (US-Japan vs. North Korea-China-Russia) and Support for Nuclear Armament: Analysis of the 2025 EAI East Asian Survey Results

I. The Launch of the Lee Jae-myung Administration and Record-High Support for Nuclear Armament Among South Koreans

[Figure 1] Support for and Opposition to South Korea Possessing Nuclear Weapons Amidst North Korean Nuclear Threats (2016-2025)

On June 4, 2025, President Lee Jae-myung was elected with a record 49.42% of the vote. With the Democratic Party of Korea securing a majority of 171 seats in the National Assembly, a "super majority" government, dominating both the legislative and executive branches, was established (Yonhap News 2025a; Yonhap News 2025b). Building on this strong mandate, the Lee Jae-myung administration took proactive steps to improve inter-Korean relations from its outset. Notably, the South Korean military ceased loudspeaker broadcasts towards North Korea, and North Korea responded by halting its own propaganda broadcasts towards the South, signaling positive developments (Yonhap News 2025c; Yonhap News 2025d). These changes could heighten public expectations for improved inter-Korean relations. As expectations for inter-Korean relations recovery may influence perceptions of the North Korean nuclear threat, it was anticipated that the launch of the Lee Jae-myung administration could lead to significant shifts in South Koreans' support for nuclear armament. For instance, during the "Spring of Pyeongchang" in 2018, the proportion of South Koreans supporting nuclear armament decreased to 43.3%, marking the first and only time since the East Asia Institute (EAI) began its surveys on South Koreans' foreign policy and security perceptions in 2013 that opposition to nuclear armament (50.3%) surpassed support ([Figure 1]).

Contrary to these expectations, however, the results of the 2025 public opinion survey, jointly conducted by the East Asia Institute (EAI) and Korea Research, indicate that support for nuclear armament among South Koreans has surpassed the 2024 figures, reaching its highest point since 2016. As shown in [Figure 1] and [Figure 2], the proportion of respondents who generally agree or strongly agree with the statement, "If North Korea does not abandon its nuclear weapons, South Korea should develop its own nuclear armament," reached 75.1%, a 3.7% increase from 71.4% last year. Specifically, the proportion of those who generally agree increased by only 0.1% from 34.8% to 34.9%, while the proportion of those who strongly agree increased by 3.6% from 36.6% to 40.2%. This demonstrates a further consolidation of the strong support base for indigenous nuclear armament.

What are the reasons behind the formation of this record-high public support for nuclear armament? What is the relationship between the ongoing US-China competition and the perceptions of the US-Japan vs. North Korea-China-Russia blocs, and South Koreans' support for nuclear armament? This issue brief aims to analyze the correlation between these factors by focusing on new trends revealed in the 2025 East Asian Survey, confirming that the factors influencing support for nuclear armament, identified up to last year, are still at play, and that perceptions of bloc formation are intensifying amid US-China competition. Compared to last year, perceptions of the North Korean threat have increased, and negative perceptions of President Trump have become distinct, while trust in US extended deterrence has decreased. Therefore, the increased support for nuclear armament can be seen as a reflection of the current deterioration of inter-Korean relations and anxieties about the extended deterrence provided by the United States. However, the majority response indicating that inter-Korean relations are expected to improve under the new administration also reflects the complex sentiments of South Koreans regarding the North Korean issue.

[Figure 2] Degree of Agreement with South Korea's Nuclear Armament (2024-2025)

II. Characteristics of the 2025 Survey Results: Perceptions of Inter-Korean Relations, Clarity of US-China Strategic Competition, and North Korea-Russia Closeness

Although support for nuclear armament has increased this year compared to last year, this does not mean that public evaluation of current inter-Korean relations has become more negative or that expectations for future inter-Korean relations have decreased. Despite the outwardly worst inter-Korean relations following North Korea's declaration of "hostile two-state relations" at the end of December 2023, evaluations of current inter-Korean relations and prospects for inter-Korean relations in 10 years have shown some improvement this year compared to 2024. As shown in [Figure 3], the proportion of respondents who answered that current inter-Korean relations are "very" or "somewhat bad" decreased by 6.9% from 83.2% last year to 76.3% this year, while the combined proportion of responses indicating "neutral" or "somewhat good" increased by 6.9% from 16.5% to 23.4%. The proportion of responses predicting deepening inter-Korean confrontation slightly decreased from 15.8% to 13.4%, while the proportion of responses expecting improvement in inter-Korean relations increased by 8.7% from 22.5% to 31.2% ([Figure 4]). Notably, expectations for improved inter-Korean relations were higher among progressives (47.2%) compared to conservatives (19.6%).

[Figure 3] Current Inter-Korean Relations (2024-2025)

[Figure 4] Prospects for Inter-Korean Relations in 10 Years (2024-2025)

Therefore, it can be inferred that the evaluation or future prospects of inter-Korean relations themselves are unlikely to be strongly correlated with the rise in support for nuclear armament among South Koreans. If so, what factors have driven the record-high support for nuclear armament this year? Clues can be found in the new responses from respondents this year regarding the most pressing threats facing South Korea and the most important diplomatic relations. As clearly shown in [Figure 5], the proportion of respondents who identified North Korea's nuclear and missile threats as the most significant threat facing South Korea steadily increased from 2021 to 2023, reaching a peak of 56.3% in 2023. However, from 2023 to 2025, this trend reversed, falling to 33.2% this year, returning to a level similar to 2021. In contrast, the proportion of respondents who identified US-China strategic competition and conflict as the most significant threat facing South Korea showed an increasing trend from 2023 to 2025, reaching a five-year high of 64.9%. [Figure 6] also shows that the proportion of respondents who selected the ROK-US relationship as the most important diplomatic relationship for South Korea reached a record high of 90.7% this year, while the proportions for inter-Korean relations and ROK-China relations were similar, at 42.2% and 43.2%, respectively.

[Figure 5] Most Pressing Threats Facing South Korea (2021-2025)

[Figure 6] Most Important Diplomatic Relations for South Korea (2021-2025)

In summary, amidst the persistent clarity of US-China competition, regardless of whether it was the Trump administration, the Biden administration, or a second Trump administration, the situation where North Korea has become closely aligned with Russia, triggered by the war in Ukraine, may be related to the rise in support for nuclear armament. Therefore, this paper aims to confirm whether the factors influencing support for nuclear armament, emphasized in previous studies (threat perception, alliance variables, political ideology and partisanship, age variables, etc.), are still at play through regression analysis, and simultaneously examine whether the rapidly emerging perception of bloc formation (US-Japan vs. North Korea-China-Russia) has a significant correlation with the surge in support for nuclear armament.

III. Statistical Analysis: South Koreans' Public Opinion on Nuclear Armament in 2025 and Perceptions of US-Japan vs. North Korea-China-Russia Bloc Formation

The 2025 East Asian Survey was conducted as a web-based survey of 1,509 panelists, proportionally allocated by region, gender, and age based on demographic information as of late April 2025. The survey was carried out on June 4th and 5th, immediately after the presidential election. A detailed overview of the survey methodology is provided in [Table 1]. Regarding South Koreans' perceptions of bloc formation amid US-China competition, in addition to existing questions asking about support for strengthening ROK-US-Japan security cooperation, a question was added asking about the strategy North Korea is expected to pursue towards Russia and China. First, to identify the variables influencing South Koreans' support for nuclear armament, regression analysis was performed, confirming the influence of key variables identified in the 2024 EAI Issue Brief analysis (Kim Yanggyu 2024). Furthermore, a statistically significant positive correlation was found between supporting ROK-US-Japan security cooperation and expecting North Korea to align closely with Russia and China, and supporting nuclear armament.

[Table 1] 2025 EAI East Asian Survey

1. Variables Influencing South Koreans' Support for Nuclear Armament: North Korean Nuclear Threat, Extended Deterrence Credibility, and Perceptions of Bloc Formation

Existing research on extended deterrence credibility and nuclear proliferation identifies security threats, the credibility of security commitments provided by allies, the international political status and prestige of nuclear-armed states, and domestic political forces advocating for nuclear armament as primary factors driving public opinion towards nuclear armament (Sagan 1996-1997; Singh and Way 2004; Jo and Gartzke 2007; Solingen 2007; Kroenig 2009; Bleek 2010). The analysis of the 2024 EAI East Asian Survey results confirmed (1) perceptions of the North Korean nuclear threat, (2) doubts about the credibility of US extended deterrence, and (3) a greater likelihood of supporting nuclear armament among those with stronger conservative political leanings (Kim Yanggyu 2024). This year's survey also employed ordinal logistic regression analysis to examine the influence of these variables and whether perceptions of US-Japan vs. North Korea-China-Russia bloc formation have a statistically significant impact on support for nuclear armament. As mentioned earlier, South Korea's support for nuclear armament was measured on a 5-point Likert scale, and the statistical analysis results are presented in [Table 2].

[Table 2] Factors Influencing Support for South Korea's Independent Nuclear Armament

* p<0.05, ** p<0.01, *** p<0.001

( ) indicates t-value

As expected, perceptions of threat from North Korea and the sufficiency of U.S. extended deterrence significantly influence perceptions of nuclear armament (Models 1-5). Specifically, the more individuals believe a preemptive strike by North Korea is likely and that U.S. extended deterrence is insufficient to counter the North Korean nuclear threat, the more likely they are to support South Korea's independent nuclear capability. Perceptions of current and future inter-Korean relations show no significant correlation.

The perception of bloc alignment, a novel focus in this analysis, was measured through respondents' support for security cooperation among South Korea, the United States, and Japan, and their perceptions of North Korea's future strategies toward China and Russia. Both variables consistently proved to be statistically significant (Models 3-5). This implies that individuals who support security cooperation among the three nations and perceive North Korea as aligning with the Sino-Russian bloc by simultaneously strengthening ties with both Russia and China tend to support South Korea's nuclear armament. Support for specific political parties, generational factors, and political ideology also emerged as significant factors (Models 4-5). Support for the People Power Party, older age, and conservative political orientation continue to significantly influence nuclear armament support, consistent with findings from the previous year's survey.

2. Factors Influencing Support for Trilateral Security Cooperation among South Korea, the United States, and Japan

Who, then, supports security cooperation among South Korea, the United States, and Japan? Using support for trilateral security cooperation as the dependent variable, we added a model incorporating perceptions of the U.S.-China conflict as an independent variable. This model utilized data from respondents who selected military support (ammunition support to troop deployment) among possible actions South Korea could take in the event of a Taiwan Strait contingency, and those who identified the U.S.-China conflict as the greatest threat to South Korean security ([Table 3]).

[Table 3] Factors of Support for Trilateral Security Cooperation among South Korea, the United States, and Japan

* p<0.05, ** p<0.01, *** p<0.001

(t-values in parentheses)

Models 2-5 confirm that individuals who believe South Korea should militarily support and intervene if a military conflict occurs between the U.S. and China in Taiwan tend to strongly support trilateral security cooperation among South Korea, the U.S., and Japan. It was confirmed that individuals who responded that the greatest threat to South Korea's security is the U.S.-China conflict tend to support the strengthening of security cooperation among South Korea, the U.S., and Japan (Models 3-4), but this statistical significance disappeared in models that included other control variables.

In addition, perceptions of the North Korean threat, support for the People Power Party, independents, and conservative political orientations show a statistically positive correlation with support for trilateral security cooperation among South Korea, the U.S., and Japan. These variables were all used in the previous regression analysis models, and their statistically significant influence in both regression analyses implies the existence of a multicollinearity problem. To confirm this, this study separately performed a linear regression model for the independent variables used in the analysis and checked the Variance Inflation Factor (VIF). The analysis results showed that the VIF values for all variables were 2.29 or lower, which is well below the generally problematic threshold of 5-10 or higher.

Furthermore, while supporters of the Democratic Party of Korea tend to be less supportive of security cooperation among South Korea, the U.S., and Japan, this was not statistically significant. Meanwhile, independents, who can also be considered centrist or undecided, showed a tendency to relatively support security cooperation among South Korea, the U.S., and Japan more than Democratic Party supporters, and this was statistically significant. Those who selected North Korea's nuclear capabilities as the greatest threat to South Korea's security also showed a tendency to support security cooperation among South Korea, the U.S., and Japan, as evidenced by a statistically significant positive correlation across Models 1, 3, 4, and 5.

In summary, individuals who perceive the North Korean nuclear threat as the greatest threat or who believe South Korea should militarily support and intervene in the event of a U.S.-China conflict in the Taiwan Strait tend to support trilateral military cooperation among South Korea, the U.S., and Japan. This implies that the stronger the perception of the North Korean threat or the perception of bloc formation due to the U.S.-China conflict and the Taiwan crisis among South Koreans, the higher the likelihood of supporting security cooperation among South Korea, the U.S., and Japan.

3. Factors Influencing Perceptions of North Korea's "New Cold War" Strategy

Another axis of the perception of bloc formation, namely trilateral security cooperation among South Korea, the U.S., and Japan, discussed above, is the perception that North Korea is closely aligned with China and Russia. Given North Korea's recent actions, such as its participation in the Russia-Ukraine war after the collapse of the Hanoi summit in 2019 and its signing of a military cooperation treaty with Russia for mutual military support, we hypothesized that these actions have had some impact on South Koreans' perception of bloc formation and conducted an additional regression analysis ([Table 4]).

We examined the variables that influenced the choice of the option stating that North Korea would align closely with China and Russia, a newly added question in this year's survey (Question 47). Specifically, individuals who perceived a high probability of North Korea launching a preemptive nuclear strike tended to perceive that North Korea was adopting a strategy of aligning with China and Russia. Similarly, those who considered the North Korean threat as the greatest security threat faced by South Korea showed a tendency to strongly perceive the formation of a North Korea-China-Russia bloc. However, as shown in Models 4 and 5, this significance weakened when other control variables were added.

Interestingly, the variable concerning South Korea's military support in case of a Taiwan contingency, which showed a significant positive correlation with support for trilateral security cooperation among South Korea, the U.S., and Japan, exhibited a statistically significant negative correlation in Models 3-5. This can be interpreted as follows: individuals who believe South Korea should actively intervene militarily in the event of a U.S.-China military conflict in Taiwan tend to have a lower perception of North Korea aligning closely with China and Russia to form a strong bloc. Further analysis is needed on this point, but intuitively, individuals who support active South Korean intervention in the Taiwan issue may perceive that the phenomenon of North Korea-China-Russia solidarity or bloc formation is difficult to maintain. Meanwhile, supporters of the People Power Party and older individuals show a significant positive correlation with the perception of North Korea-China-Russia bloc formation. For supporters of the Democratic Party, a significant positive correlation was observed only in Model 4; in models including other variables, it did not have a significant impact.

IV. Conclusion and Policy Implications

The regression analysis of the 2025 East Asia Perception Survey results presented above newly confirms that perceptions of bloc formation between South Korea-U.S.-Japan and North Korea-China-Russia, which have become more pronounced amidst U.S.-China competition, significantly influenced South Koreans' support for nuclear armament, which reached its highest level this year. While expectations for improved inter-Korean relations are evident among respondents with progressive political ideologies following the inauguration of the new government, the public opinion supporting nuclear armament has increased compared to last year, particularly among supporters of the People Power Party, older individuals, and conservatives, alongside the perception of bloc formation driven by U.S.-China competition and the challenging security reality. Notably, support for nuclear armament was also confirmed among respondents who are independent voters, with no particular party affiliation.

These analytical results suggest that given the already high level of public support for nuclear armament, the preference for nuclear weapons may intensify as discourses of a "new Cold War" or bloc formation gain traction. The current confrontational structure between South Korea-U.S.-Japan and North Korea-China-Russia differs significantly from the ideological confrontations of the past Cold War era. The U.S. no longer assumes the role of the leading power of the liberal bloc and is increasingly adopting a transactional approach toward its allies. China, not Russia, is the core country providing practical capabilities in the North Korea-China-Russia alignment. Furthermore, the U.S.-China strategic competition is not a contest for absolute hegemony that either side can unilaterally consolidate at present, nor can it be simply reduced to an ideological confrontation.

Therefore, the Lee Jae-myung administration needs to explain the 21st-century U.S.-China competition, which is unfolding in a form different from the past Cold War, using more sophisticated policy language and be mindful of not stimulating public opinion for nuclear armament in South Korea. In particular, as confirmed by the regression analysis results, while there is a clear tendency for support for strengthening security cooperation among South Korea, the U.S., and Japan and for South Korea's military support in case of a Taiwan contingency to increase as U.S.-China competition intensifies in the perception of South Koreans, it is important to remember that this does not necessarily directly lead to perceptions of strengthened North Korea-China-Russia cooperation and bloc formation. Perhaps South Koreans are already facing the complex East Asian security reality that cannot be captured by simple dichotomies such as 'South Korea-U.S.-Japan versus North Korea-China-Russia' or 'new Cold War.' ■

References

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■ Kim Yang-gyuProfessor, National Defense University.

Oh In-hwanSenior Research Fellow, East Asia Institute.

■ Responsible Editor: Oh In-hwanSenior Research Fellow, East Asia Institute

Inquiries: 02 2277 1683 (ext. 202) | ihoh@eai.or.kr