BCP Social Sciences & Humanities HASS 2022 Volume 18 (2022) 387 Research on Korean Foreign Policy since Park Geun-hye Administration from the Perspective of Neoclassical Realism -- A Case Study of the THAAD Issue Bohua Gao* Dehai Class, Yanbian University, Yanji, China. gbh1026-@naver.com Abstract. The pervasiveness of Sino-US relations is profoundly reflected in many regions all over the world. As a wrestling field for various forces, Korean Peninsula has a self-evident strategic value to China and the United States, especially in the terms of military security and geostrategy. Due to the sophisticated environment in Northeast Asia, it is necessary to make an in-depth analysis of South Korea's diplomatic decision-making mechanism based on studying the Sino-US competition system. With the help of neoclassical realism theory, we can pay more attention to the role of domestic factors in state actors. The different attitudes and decisions of Park Geun-hye administration and Moon Jae-in administration towards the THAAD system are inseparable from leaders' intentions, strategic culture, state-society relations, domestic system, and other factors. Their joint efforts under the unique political system restrict and affect the decision-making process and results of Korean diplomacy. Therefore, how these domestic factors show a combined impact on the Korean diplomatic decision-making is the key to the study. Keywords: Korean Foreign Policy, Sino-US Relations, Sino-ROK relations, the THAAD Issue, Neoclassical Realism. 1. Introduction At present, the world is undergoing an earth-shaking change that has never been seen in a century. For China, how to grasp the opportunity of the times and well handle international relations has become an urgent task. As the top two economies in the world, both China and the United States are permanent members of the United Nations Security Council, playing an important role in the international community. Therefore, the development of Sino-US relations can profoundly change the trend of the world pattern evolution. Sino-US competition has entered a brand-new historical juncture. A rising power, China, has always firmly adhered to peaceful development, with an aim to achieve its own goals and promote cooperation and prosperity of all countries in the world. However, the United States regards China as a potential rival for its world hegemony. In 2018, the then US President Donald Trump started a trade war with China, imposing tariffs on Chinese goods and setting up trade barriers in an attempt to change the so-called unfair trade. Joe Biden, the current US President, has continued the Trump administration's attitude towards China to a certain extent, wooed his allies to establish the Indo-Pacific Economic Framework (IPEF), so as to build a small multilateral organization excluding China and technically isolate China. In recent years, South Korea's hard power and soft power have developed by leaps and bound. As a medium-sized power with development potential, South Korea's economic aggregate has ranked among the top ten in the world, with its military strength ranking sixth worldwide. In addition, South Korea have strong geographical relations with China throughout history. For example, the Sui Dynasty was hardly weakened by three expeditions to Goguryeo launched by Emperor Yang of Sui; the Korean Donghak Peasant Revolution triggered the First Sino-Japanese War which kicked off the fall of the Qing Dynasty; the War to Resist US Aggression and Aid Korea in the Korean War period built a stable external environment for founding the People’s Republic of China. Thus, it is easy to see that the Korean Peninsula has always been crucial to China's external security and its national development. BCP Social Sciences & Humanities HASS 2022 Volume 18 (2022) 388 The importance of Northeast Asia to China is self-evident and the THAAD issue has directly affected China's national security. For any country, safeguarding its own survival is an insurmountable bottom line. In current international society, the status of military means has declined in the process of realizing national interests, but the military itself has always been vital as usual. Every decision of South Korea will not only affect Sino-South Korea relations, but also Sino-US relations, North Korea-South Korea relations, South Korea-Japan relations, and Sino-Japanese relations. It’s precise because the Korean Peninsula has involved various forces and contradictions that the impact of South Korea's strategic choice on China's national security is momentous. As one of the important countries in East Asia, South Korea has a significant strategic position explained above. As far as the current situation is concerned, it’s worth noting that the US-South Korea alliance remains the cornerstone of South Korea's foreign policy. In addition, China's influence on South Korea has forced it to be cautious about its words and deeds, so South Korea is often in a dilemma between China and the United States. Confronted with South Korea, China regards it as a potential partner, while the United States deems it as an ally that must be wooed. Just as Xing Haiming, China's ambassador to South Korea, said: "South Korea should not choose between China and the United States, but make its decision according to its own interests"[1]. With regard to China, it’s unacceptable for the United States to turn South Korea into a pawn to contain China. 2022 marks the 50th anniversary of Nixon's visit to China and the 30th anniversary of diplomatic relations between China and South Korea. During this important historical period, re-examining and planning Sino-US relations and China-ROK relations is of great importance to China's strategic wisdom to go global from Asia. At present, the foreign policy conception of Yoon Suk-yeol, the current president of South Korea, is to actively cooperate with the United States to exert pressure on China and build a comprehensive strategic alliance with the United States based on the existing alliance. In the era of strategic Sino-US competition, the foreign policy of South Korea is beneficial to America but alienates China, which will put China at risk. With the increasingly fierce strategic competition between China and the United States, summing up the logic behind the foreign policy of the previous Korean administration can help us predict the foreign policy trend of the new conservative Korean administration in advance and make preparations for it. In addition to stabilizing China-ROK relations and the situation in Northeast Asia, it’s also crucial to promote the overall layout of China's diplomatic strategy and safeguard China's national security. 2. Neoclassical Realism Theory and Formulation of South Korea’s Foreign Policy The theory of international relations can help us to better clarify the complicated phenomena of international relations. As Kenneth Waltz said, the theory has the functions of description, explanation, and prediction, so we also need to thoroughly study certain theories to better understand South Korea's foreign policy. This paper from the perspective of neoclassical realism theory is to describe, analyze, and summarize its foreign policy under the Sino-US competition system. 2.1 Overview of Neoclassical Realism Theory Realism theory is one of the important schools of international relations theory. With some differences in realism theory, most realism theory follows similar theoretical assumptions. It generally accepts the assumption that the international community is anarchy due to the lack of supreme authority in the international community, so every country has to take self-help to cope with this situation. At the same time, anarchy leads to power politics and endless international conflicts, hindering international cooperation. Accepting these basic assumptions, neoclassical realism further expounds on international relations. First of all, compared with structural realism which focuses on the influence of power structure on actors in the international system, neoclassical realism combines system variables with domestic BCP Social Sciences & Humanities HASS 2022 Volume 18 (2022) 389 variables. The outlook and ambition of a country's foreign policy are the first subject to its position in the international system, that is, its relative material strength. However, this system pressure can only work through several intervening systemic variables. Secondly, neoclassical realism holds that countries are neither homogeneous nor functional. System pressure determines the general foreign policy but fails to determine the specific details of state behavior. From the perspective of logic, neoclassical realism regards the relative power distribution between countries as an independent variable, which is influenced by intervening variables such as domestic constraints and elite cognition in the transmission, and finally can be indirectly transformed into foreign policy. (as shown in Figure 1). 2.2 System Pressure Faced by South Korea and Domestic Factors Affecting Decision-Making Neoclassical realism can make up for the shortcomings of other theories to well explain South Korea's foreign policy. From the perspective of classical realism or structural realism, the decision- making changes of the South Korean government are inconsistent with the actual situation. For example, from the theory of classical realism or structural realism, the system pressure faced by South Korea increased from the Park Geun-hye to the Moon Jae-in period. At this time, the US-South Korea alliance will be more closed under the external forces and South Korea's foreign policy should somehow serve the United States. However, it was during the Park Geun-hye administration that South Korea chose to deploy THAAD, which worsened Sino-Korean relations to the extreme. During the Moon Jae-in administration, confronted with the Trump administration's endless pressure on China, it chose to mediate between China and the United States to ease its relations with China and North Korea. Therefore, this seemingly irrational phenomenon needs to be explained by neoclassical realism. As for South Korea, the pressure of the international system stems from the growing fierce Sino- US competitions and conflicts. Besides, there is a huge gap between the strength of South Korea and the big countries, making it hard to make diplomatic decisions. In addition, North Korea adjacent to South Korea often takes unpredictable actions, which makes South Korea under more external pressure and aggravates the instability of the Korean Peninsula situation. In such an external environment, South Korean leaders' intention, strategic culture, state-society relations, domestic system, and other domestic factors also play an important role in its foreign policy-making. (as shown in Figure 2). Figure 1: Theoretical Logic of Neoclassical Realism (Source: Norlin Ripsman et al., Neoclassical Realism Theory of International Politics, translated by Liu Feng et al., Shanghai People's Publishing House, 2017 edited, p. 34) BCP Social Sciences & Humanities HASS 2022 Volume 18 (2022) 390 Figure 2: Formulation of South Korean Foreign Policy from the Perspective of Neoclassical Realism (Source: author’s own idea) 3. Policy Analysis of Park Geun-hye Administration's Deployment of THAAD The deployment of the THAAD system is a diplomatic issue encountering both Park Geun-hye and Moon Jae-in administrations. The different attitudes of these two administrations towards the THAAD system are vital to Sino-South Korea relations. Up against Sino-US competition, the South Korean government faces diverse system pressures and domestic factors in each period. Given that the mechanism of these factors in South Korean foreign policy-making is relatively stable, it’s imperative to choose the deployment of THAAD as a research case, which can provide a useful reference for describing, explaining, and predicting such issues. 3.1 Analysis of Reasons for the Deployment of THAAD by the Park Geun-hye Administration North Korea conducted its fourth nuclear test in January 2016, directly leading to high tension between the North Korea-South Korea relations and DPRK-US relations. The Park Geun-hye administration decided to deploy THAAD in such an external environment. With China's rise undermining American hegemonism, the United States gradually regards China as its strategic opponent. The structural contradictions between China and the United States have emerged, which inflicts South Korea with increasing system pressure and complicates the relations among Northeast Asian countries. Since the bombardment of Yeonpyeong in 2010, North Korea- South Korea relations have always been in tension without any mitigation after North Korea's frequent nuclear tests strongly threatening South Korea. The systematic factors of intensified Sino- US competition and North Korea’s intervention both have laid the groundwork for the Park Geun- hye administration to deploy THAAD in the future. 3.1.1. Park Geun-hye's Personal Attitudes Park speaks some Chinese and has a certain understanding of Chinese culture, which plays a good role in strengthening the Sino-South Korea bonds. Attaching great importance to Sino-South Korea relations since she took office, she firstly changed the order of visits from "the United States, Japan, China, and Russia" to "the United States, China, Japan, and Russia". Although Cheongwadae spokesman said, "The order of this visit is out of a normal adjustment without any tendency or political meaning." But relations between China and South Korea were indeed at their best because BCP Social Sciences & Humanities HASS 2022 Volume 18 (2022) 391 of Park's proactive attitude toward China, and such diplomatic intimacy gained more attention when Park boarded Tiananmen Gate to celebrate the military parade on September 3. During this period, frequent Sino-South Korea official exchanges also led to the successful signing of the Sino-South Korea Free Trade Agreement. Park Geun-hye put forward the Dresden concept targeting the reunification of the Korean Peninsula on March 28, 2014, which was subsumed under three major schemes including humanitarian assistance, restoration of North Korea-South Korea homogeneity, and the building of people's livelihood infrastructure. Although this concept had not been recognized by the DPRK, its attitude towards the DPRK was relatively moderate. However, North Korea conducted two nuclear tests in 2016, undercutting Park’s scheme and confidence. At this time, Park Geun-hye hoped that China could take the initiative to exert pressure on the DPRK by establishing friendly relations with China, which was well reflected in Park Geun-hye's speech to the nation. But the exchange between China and South Korea on this issue had not made substantial progress, which also changed Park Geun-hye's attitude towards China from expectation to disappointment. Therefore, in the later period of her administration, South Korea's pressure on North Korea became tougher, and China-South Korea relations also deteriorated sharply with the deployment of the THAAD system. 3.1.2. Conservative Strategic Culture As the right-wing in South Korean politics, Park Geun-hye's administration was also deeply influenced by right-wing thoughts. With its conservative strategic culture and pro-American tendency in foreign policy, Park Geun-hye took tough policies towards the DPRK and was more inclined to exert pressure on the DPRK to solve the Korean nuclear issue, so as to realize the reunification of North Korea and South Korea. First of all, members of Park Geun-hye's decision-making team were strongly conservative. The identity of the whole team and its strategic culture decided their determination to contain North Korea. After failing to win over China to participate in sanctions against North Korea, it became more determined to solve the problem through the US-South Korea alliance.[2] Secondly, as for the right wing politics itself with a dualistic mindset, diplomatic means such as pressure, coercion, and sanctions are the products of this strategic culture. As unresolved realistic and historical issues, the Korean nuclear issue and the reunification of the Korean Peninsula interweave the interests of all parties with extreme complexity. In addition, the national character and morale shaped by North Korea for many years made it impossible to reach a compromise. Thus, it was reasonable for the right-wing strategic culture to add fuel to the Korean peninsula situation. In addition, the two major parties in South Korea are in power alternately, which was an obstacle to guaranteeing the stability of foreign policy and directly deteriorated South Korea's attitudes towards the DPRK. 3.1.3. State-Society Relations During the Park Geun-hye Period Since Park Geun-hye took office, Sino-South Korea official exchanges have increased day by day. But South Koreans remained to have higher affection for Americans than the Chinese. According to a report by Asan Institute for Policy Study, South Koreans' favorable opinions of the United States had been about 6 points with a small fluctuation from January 2016 to March 2017. On the other hand, that of China has been lower mostly at 4 to 6 points with a downward trend during this period. In addition, the data in March 2017 even fell below the 4 points at only 3.21, which was less than Japan's 3.33 points [3]. The above data shows that the amicable image of the United States for South Koreans is irreplaceable. In terms of foreign goodwill, South Koreans preferred the United States to China, which hadn’t been changed for a long time. Therefore, the Park Geun-hye administration embraced the United States and opposed China based on a deep-seated public opinion. Due to the THAAD issue, the rapid downward of its goodwill towards China also indicated that Chinese and South Koreans’ views on each other are profoundly influenced by their respective governments. Thus, such Sino- Korean relations are destined to be relatively fragile. BCP Social Sciences & Humanities HASS 2022 Volume 18 (2022) 392 3.1.4. Overview of Congress During Park Geun-hye Period In the 2012 South Korean parliamentary elections, the ruling New Frontier Party continued to maintain its position as the largest party in the National Assembly. The seat number of Moon Jae-in's Democratic United Party has nearly doubled with the greatly enhanced strength. In the same year, Park narrowly defeated Moon Jae-in in the presidential election, but the competition between the two parties in Congress was still in tension. Park Geun-hye's ruling party continued its dominant position in Congress and didn’t lose any ground in the various competitions. Therefore, the conservative South Korean National Assembly provides favorable conditions for Park Geun-hye’s administration to deploy THAAD. At the end of Park Geun-hye's administration, the South Korean National Assembly held a new election in April 2016, where the Democratic United Party had become the largest party and Park Geun-hye's New Frontier Party lost control of parliament. But at this time, Park Geun-hye herself had been impeached and the conservative parliament was declining, so she failed to occupy the mainstream. Therefore, this congressional election further confirmed the end of Park Geun-hye's era and then laid a political foundation for the foreign policy change of the next administration. 3.2 Impact of the Park Geun-hye Administration's Foreign Policy During Park Geun-hye's administration, the shift hedging strategy strengthened the oligarch of the United States in South Korean diplomacy.[4] South Korea's diplomatic autonomy had also been weakened to some extent. South Korea went its way to deploy THAAD in its country, which was the target of public criticism. It even signed the South Korea-Japan Military Intelligence Sharing Agreement and the General Security of Military Information Agreement with Japan, escalating the situation in Northeast Asia again. China, Russia, and the DPRK had paid great attention to the Asian version of NATO led by the United States. In essence, South Korea's foreign policy was inseparable from that of the United States. However, South Korea's domestic factors also gave a direct play in foreign policy formulation. The compound effect of many factors affected all aspects of Park Geun- hye's foreign policy. Although it can't be denied that the Park Geun-hye administration had made positive efforts to solve the Korean Peninsula issue, the Park Geun-hye administration's foreign policy undercuts the peaceful situation in Northeast Asia. With China-South Korea relations worsening, China and South Korea were at odds with each other. In particular, it undermined their political mutual trust, which greatly hindered their friendly cooperation. Since 2016, China has imposed a series of bans on literature, art, and tourism in South Korea. Regarding this as China's countermeasure and retaliation against its deployment of THAAD, South Korea had economically lost about 850 million trillion, accounting for about 0.5% of GDP. Meanwhile, the North Korean nuclear issue has not been solved and even presents a tense trend and the reunification of the Korean Peninsula has also suffered serious setbacks. Therefore, South Korea itself has fallen into a relatively passive situation. To sum up, the Park Geun-hye administration's foreign policy has led to the retrogression of regional relations in Northeast Asia. 4. Analysis of the Moon Jae-in Administration's Policy towards THAAD 4.1 Reasons for the Moon Jae-in Administration’s "Three Noes" Commitment Moon Jae-in’s administration faces a very difficult diplomatic environment. Since US President Trump took office, the US suppression of China has ushered in a new stage. Although China has no intention of conflicting with the United States, the trend of Sino-US relations from competition to confrontation was more and more obvious. Compared with the Park Geun-hye administration, the Moon Jae-in administration confronted nearly the same overwhelming systemic pressure from Sino- US relations. Moreover, the THAAD issue had brought Sino-South Korea relations to the bottom and the military threat of North Korea’s fourth nuclear test had been on the rise. All these required the BCP Social Sciences & Humanities HASS 2022 Volume 18 (2022) 393 Moon Jae-in administration to formulate a reasonable foreign policy according to the reality, so as to improve its relations with China and the DPRK, promote its economic development, and realize the peace and stability of the Korean Peninsula. Elected as the President of South Korea in 2017, Moon Jae-in changed the previous attitude of the Park Geun-hye administration towards China and actively started consultations with China. In November of the same year, China’s Foreign Minister Wang Yi held talks with his South Korean counterpart Kang Kyung-wha in Beijing. They reached a consensus, especially on the principle of "three noes" put forward by the Moon Jae-in administration, that is, South Korea will not add the THAAD system or join the US anti-missile system, the security cooperation between South Korea, the United States, and Japan will not develop into a tripartite military alliance, and the use of the existing THAAD system should be restricted [5]. The reasons why the Moon Jae-in administration chose "three noes" on the THAAD issue still need to be discussed from the aspects of leaders' attitudes, strategic culture, state-society relations, and domestic systems. 4.1.1. Moon Jae-in's Personal Attitudes Moon Jae-in's personal attitudes led to his foreign policy of conciliation. His political mentor is Roh Moo-hyun, the 16th president of South Korea, whose political ideas have penetrated Moon Jae- in. On the DPRK policy, Roh Moo-hyun revised former President Kim Dae-jung's Sunshine Policy to Peace and Prosperity Policy and actively carried out balanced diplomacy, making himself a pillar of South Korean strategic balance in Northeast Asia. Based on this, Moon Jae-in's Berlin Conception came into being, which mainly includes inheriting the policies of Kim Dae-jung and Roh Moo-hyun and improving the leading role of South Korea in dealing with peninsula affairs; permitting flexible non-governmental exchanges within the framework of international sanctions against the DPRK; stopping hostilities and discussing the Korean nuclear issue and the Peace Agreement; resuming economic cooperation; promoting the inter-Korean railway connection to coordinate with the Belt and Road Initiative; building a peace mechanism in Northeast Asia through Northeast Asia Plus Responsibility Community and implementing the New Northern Policy and the New Southern Policy.[6] It is not difficult to see that Moon Jae-in's attitude towards North Korea is quite different from that of Park Geun-hye, which has been verified in the follow-up affairs. During the period of Moon Jae- in's administration, North Korea conducted its sixth nuclear test on September 3, 2017, to verify that its technology for developing hydrogen bombs has achieved great success, which inevitably led to tension in the international community. However, compared with the Park Geun-hye administration, the Moon Jae-in administration showed great restraint and did not adopt a radical policy toward the DPRK. Two months later, during the talks with China, South Korea put forward the "three noes" commitment where Moon Jae-in's political ideas made a difference. 4.1.2. Progressive Strategic Culture Although Moon Jae-in himself had always opposed the conservative accusation that he was pro- North Korea, the Moon Jae-in administration did have clear progressivism. Compared with the Park Geun-hye administration which insisted on deploying THAAD and advocated the futility of the Six- Party Talks, the foreign policy of the Moon Jae-in administration profoundly reflected the discrepancy between progressives and conservatives of South Korea. Moon Jae-in himself and his administration belonged to the left wing. Specifically, the leftists in South Korea tend to play more government roles in the domestic economy, restricting and cracking down on the business conglomerate. Although the left wing won over the United States in diplomacy as the right wing, they were more cautious rather than resistant to cooperating with China, and they eased its relations with North Korea instead of sanctioning against it. This deeply-rooted strategic culture exerts a subtle influence on the foreign policy of the Moon Jae-in administration. Korean progressives, represented by the Moon Jae-in administration, will not easily resort to the United States for their security and interests, but seek ways with their efforts. BCP Social Sciences & Humanities HASS 2022 Volume 18 (2022) 394 4.1.3. State-Society Relations During Moon Jae-in Period The THAAD issue has accumulated anti-China sentiment in South Korea, but it changed its previous attitudes towards China and eased Sino-Korean relations slightly when the Moon Jae-in administration came to power. Some South Korean scholars believed that the indicators of exchanges between China and South Korea generally showed a growth trend, which was expected to continue for some time. However, these indicators do not reflect the structural contradictions in China-ROK relations with the potential to trigger misinterpretation [7]. Trump's "America First" doctrine had affected South Koreans' goodwill towards the United States, which had dropped to 34% in the last year of his term of office. Such a phenomenon provided a favorable public opinion environment for the Moon Jae-in administration to choose the "three noes" commitment. It is worth noting that in a survey in 2021, 71.6% of South Koreans thought the United States was a trustworthy country, while China ranked last with 6.8%.[8] It can be seen that the pro- American and anti-China tone of society is hard to change. Thus, the structural Sino-South Korea contradictions still exist. 4. Overview of Congress During Moon Jae-in Period In the 2020 South Korean parliamentary election, the ruling Democratic Party of Korea and the Platform Party won an absolute advantage of more than half of the parliamentary seats. It was the first time for them to win an unprecedented three-fifths of the seats in the National Assembly since the democratization of South Korea in 1987. Therefore, the South Korean National Assembly gave the stronger support and confidence for the Moon Jae-in administration to continue its foreign policy and adopt relevant agendas. 4.2 Diplomatic Autonomy of the Moon Jae-in Administration and Hedging between China and the United States In terms of relations with the United States, the Moon Jae-in administration suspended and adjusted the number of military exercises between the US and South Korea, manifesting South Korea's attempt to reduce its dependence on the US. At the same time, he also put forward the return of wartime command from the US again, which can be regarded as a key for the Moon Jae-in administration to gain the power to control risks on the Korean Peninsula. In terms of relations with China, the Moon Jae-in administration actively sought dialogue, made a "three noes" commitment, and reached a consensus with China to deal with the Korean nuclear issue in stages. Objectively speaking, it was difficult for Sino-ROK relations to return to the best level in 2015. However, compared with the THAAD crisis in 2017, a great warming trend could be seen in mutual relations on the whole. As for relations with the DPRK, the Moon Jae-in administration put forward the New Northern Policy and New Southern Policy and insisted on dealing with inter-Korean relations through dialogue, so the non-governmental exchanges between North Korea and South Korea were boosted to some extent. In April 2018, Kim Jong-un and Moon Jae-in signed the Panmunjom Declaration, symbolizing the great repair of North Korea-South Korea relations. In addition, the mediation of the Moon Jae-in administration in the North South-US relations provided favorable conditions for the realization of the two North Korea-US summits in 2018 and 2019. To sum up, when dealing with international relations, the Moon Jae-in administration has the feature of balanced diplomacy during Roh Moo- hyun period with its distinct characteristics of the times. Although the United States is vital to South Korea, the US-South Korea alliance has always been the cornerstone of South Korea's foreign policy. However, the foreign policy of the Moon Jae-in administration was not completely controlled by the United States but had certain autonomy and flexibility. BCP Social Sciences & Humanities HASS 2022 Volume 18 (2022) 395 5. Comparison between Park Geun-hye Administration and Moon Jae-in Administration on THAAD Issue There are significant differences between the Park Geun-hye administration and Moon Jae-in administration in formulating foreign policies. Park's government wary of China was more conservative and diplomatically dependent on the United States. Meanwhile, it was eager to develop friendly relations with Japan but had a hostile policy toward North Korea. Once frustrated in the relations with the DPRK or China, it would completely turn to the United States and go against China and the DPRK. The Moon Jae-in administration was more progressive. Although its dependence on the United States had not decreased in essence, it maintained restraint and dialogue with the DPRK, treated China cautiously, and would not be fully active towards Japan. The factors affecting the foreign policy of the Park Geun-hye administration and Moon Jae-in administration are mainly divided into the above-mentioned leaders' intentions, strategic culture, state-society relations, and domestic system. Park Geun-hye and Moon Jae-in had quite different intentions. The difference in strategic culture stemmed from the opposition between conservatives and progressives, which affects many aspects of domestic politics. The relationship between state and society is integrated into decision-making and the effect of policy implementation. Finally, the domestic system, especially the relationship between the ruling party and Congress, provides a guarantee for decision-making and policy implementation. (as shown in Table 1). Table 1: Comparison between the Park Geun-hye Administration and the Moon Jae-in Administration on THAAD Issue (Source: Self-made by the author) Influence Factors of South Korean Government System Pressure Domestic Factors Sino-US relations North Korea- South Korea Relations Leaders Attitudes Strategic Culture State- Society Relations Domestic System Park Geun- hye Period Moderate Relative Tension Pro-US; Utilized China Conservative Amicable to America; Alienate China Ruling Party Had a Small Advantage Moon Jae-in Period Conflicted Slightly Moderate Policy of Conciliation; Emphasize Dialogue Progressive Amicable to America; Moderate to China Ruling Party Had a Great Advantage BCP Social Sciences & Humanities HASS 2022 Volume 18 (2022) 396 6. Prospects of Yoon Suk-yeol’s Foreign Policy after Taking Office 6.1 System Pressure and Factors of North Korea Faced by Yoon Suk-yeol Administration Biden has been accustomed to exerting pressure on China in a multilateral way since he took office. In December 2021, he held a Summit for Democracy to isolate China and Russia in the name of opposing authoritarianism and protecting human rights, so as to reaffirm the US leadership over the Western free world. In addition, the United States is now wooing many countries, including South Korea, to establish an Indo-Pacific Economic Framework and exclusive industrial chain that excludes China. While Chinese scholars generally believed that it would not have a too negative impact on Sino-ROK relations and there was no need to be pessimistic even if Yoon Suk-yeol was elected president of South Korea. Although South Korean conservatives tried their best to be close to the United States, they would not alienate China thanks to China's immeasurable influence on its economy [9]. However, at present, the economic decoupling between China and the United States has gradually turned into reality, which is bound to arouse China's vigilance. If South Korea conforms to the economic strategy of the United States and uses the so-called Indo-Pacific Economic Framework to neutralize the importance of trade with China, it will inevitably make China lose its economic advantage and significance to South Korea. Although a considerable Sino-US gap in strength exists, China does lose its economic indispensability and falls into a passive position. Despite a long process, we must pay full attention to the words and deeds of the countries concerned. In addition to the systematic stimulation of the Sino-US game to South Korea, the actions of North Korea also make it hard to solve the Korean peninsula issue. South Korea's presidential office stated on May 25, saying that North Korea had conducted start-up tests on nuclear-initiating devices at Punggye-ri Nuclear Test Site and other places. In addition, the DPRK launched eight missiles in succession on June 5, 2022, as a counterattack against the just-concluded US-South Korea military exercise. 6.2 Some Statements of Yoon Suk-yeol’s Administration on Foreign Relations In his first press conference after running for and taking office in South Korea’s presidency, Yoon Suk-yeol made some statements on the foreign policy of the new South Korean administration. This paper summarizes them as follows: 6.2.1. Rebuild the ROK-US Alliance and Strengthen the All-round Strategic Alliance The pro-American principle remains unchanged in Yoon Suk-yeol’s government which even wants to establish a global comprehensive strategic alliance with the United States. In order to restart the deployment of THAAD, his administration joined the Quadrilateral Security Dialogue (QUAD) and the India-Pacific Economic Framework (IPEF). 6.2.2. Develop Mutually Respectful ROK-Sino Relations Yoon Suk-yeol also talked about developing mutually respectful ROK-Sino relations at the press conference, actually hoping that China can give South Korea due respect. Compared with defining China as an economic competitor during the election campaign, his tough attitude towards China has changed slightly, but he has not made any promises. So we still need to wait and see. 6.2.3. Build a Future-oriented ROK-Japan Relations Yoon Suk-yeol released the signal of improving its relations with Japan to bridge conflicts between the two sides and strengthen the exchanges between the younger generation of South Korea and Japan. Besides, it also wants to mitigate the differences between South Korea and Japan in security and history. From this point of view, Yoon Suk-yeol’s government may be more active in developing bilateral relations between South Korea and Japan. BCP Social Sciences & Humanities HASS 2022 Volume 18 (2022) 397 6.2.4. Always Be Open to the Dialogue with North Korea and Get Ready to Respond to Any Provocation by North Korea Although Yoon Suk-yeol wanted to restore normal North Korea-South Korea relations and promote the peninsula’s denuclearization, he was still wary and hostile to North Korea. His statement about North Korea has many similarities with Park Geun-hye’s. For example, the North Korea-South Korea dialogue depends on North Korea's attitude. In combination with history, South Korea's attitude and thinking may only superficially solve the Korean nuclear issue but fail to play a substantial role. 6.3 Trend of South Korea's Foreign Policy Under Yoon Suk-yeol’s Administration The domestic and international environment faced by the new South Korean administration is complex, which is analyzed as follows: In November 2021, the heads of China and the United States held an online meeting. China has proposed three baselines for Sino-US relations, hoping that the US will ensure avoiding conflicts. However, the long-standing hegemonic tradition and Cold War mentality of the United States doomed the Sino-US competition to be constantly frictional crossing the bottom line. As an ally of the United States, South Korea also has its position and interests. Scholars of East Asian studies in South Korea have made the following suggestions to the new government at the ROK-US Summit: South Korea needs to clarify its position and values, and strengthen economic and security cooperation between South Korea and the United States with the goal of opening multilateralism. Moreover, it should use comprehensive means to coerce North Korea, seek the recovery and expansion of cooperation between South Korea, the United States, and Japan. This article by the Institute of East Asian Studies, a conservative think tank, basically outlines the blueprint of the new government's foreign policy, which is also verified by Yoon Suk-yeol’s remarks. For a long time, China has maintained a huge advantage in economic volume over South Korea with a widening gap, which has had a great impact on the mentality of South Korean society. The South Korean government and people have formed a false perception: when it comes to military security issues, China will hold the economic advantage to suppress South Korea and China even has a unique influence on North Korea. From China's point of view, the strength of China and South Korea is not equal. China often regards South Korea as a strategic pawn arranged by the United States in Northeast Asia and criticizes the independence of its foreign policy. According to the domestic situation in South Korea, Yoon Suk-yeol’s government still faces many problems after taking office. It can be concluded from the voting results in the presidential election that the social division in South Korea, including the regional division, the division between youngsters and elderly groups, and the gender division is ubiquitous, which makes South Korea filled with unstable factors. Some Chinese scholars have taken a negative attitude towards its situation. First, the ruling party is conservative, but the South Korean National Assembly is still dominated by progressives, which will constrain Yoon Suk-yeol’s government to a certain extent. Moreover, it is difficult to change the minority government of South Korea until 2024. The redistribution of power in local elections remains uncertain and the South Korea's tradition of political purge threatens to destabilize the political situation.[10] A series of domestic challenges facing the new government will have an incalculable impact on its foreign policy. To sum up, due to the comprehensive domestic and foreign factors, South Korea's foreign policy is still unclear. 7. Conclusion From the Park Geun-hye administration to the Moon Jae-in administration, the system pressure from China and the United States is increasing. Both governments have suffered tremendous external stimuli, but they have chosen diametrically opposite decisions and obtained different results. In this process, leaders' intentions, strategic culture, state-society relations, and domestic systems all play BCP Social Sciences & Humanities HASS 2022 Volume 18 (2022) 398 different roles. The South Korean government's diplomatic decision-making is based on these key factors, so the decision-making has its realistic conditions and logical chain. The deployment of THAAD depends on the intensification of Sino-US structural contradictions, the stimulation of North Korea, and the domestic factors of South Korea. Based on the judgment of reality, the Park Geun-hye administration turned to favorable conditions for the deployment of THAAD, which produced, passed, and implemented the decision to deploy THAAD. However, under the pressure of the international environment (including the fourth nuclear test of North Korea), the Moon Jae-in administration took the initiative to change the unfavorable diplomatic situation. With the comprehensive effects of domestic factors, the "three noes" policy put forward by the Moon Jae- in administration has been formulated and implemented, which achieved ideal results that it has kept a proper distance from the United States, Sina-ROK relations and North Korea-South Korea relations have been repaired to some degree in a short time. At present, up against the new trend of Sino-US competition, the system pressure faced by Yoon Suk-yeol’s government will not decrease, its foreign policy decision-making and implementation are still influenced by domestic and foreign factors. Although the new government has not made major actions to stimulate China currently, it still has a potential threat. Thus, we should make corresponding countermeasures. Firstly, we should take advantage of the 30th anniversary of the establishment of Sino-ROK diplomatic relations to deepen exchanges and cooperation. Secondly, we should firmly emphasize the red line of national interests, carefully deal with South Korea's foreign policy, and use asymmetric advantages to enhance South Korea's dependence on China, so as to prevent it from completely turning to the United States. Finally, we should try to figure out the wishes, goals, and characteristics of the South Korean government and take the corresponding actions timely to unswervingly safeguard and develop the interests of China. References [1] Xing, H. M. (2017, July 16). Sino-ROK relations are not an accessory to ROK-US relations. JoongAng Ilbo. (29). [2] Xie, B. & Wang, X. K. (2017). An analysis of South Korea policy adjustment towards China from the perspective of diplomatic decision-making model based on the study on Park Geun-hye administration. Journal of Liaoning University (Philosophy and Social Science Edition), 45(04), 149-158. [3] Kim Ji-yun, Gangworm & Lee, hyoung. (2017, March 19) THAAD deployment on the Korean peninsula and South Koreans' perception of neighboring countries changing rapidly. Issue Brief. [4] Gu, J. W. & Su, C. H. (2021, June 30). Hedging path, system pressure, and strategy utility of republic of Korea’s hedging strategy in the 21st century. Northeast Asia Forum. 30(06), 106, 121-126. [5] Ministry of Foreign Affairs of People’s Republic of China. (2019, August 28). Wang Yi held talks with ROK’s foreign minister Kang Kyung-ho. [6] Li, D. Q. (2017, July 26). Moon Jae-in's "Berlin Vision" of North Korea policy and its challenges. China Youth Daily. [7] Kim, hee-kyo. (2022, April 28). Digging into the “China hatred” of Korean society. Kukmin Ilbo. [8] Lee, Myung-ah. (2022, January 12). The country that Koreans trust the most is the United States... China, Japan, 1st and 2nd place in the distrustful countries. Unipress. [9] Wang, S. (2008). American complex of Korean diplomacy and its choice－close to America will not be estranged with China. Northeast Asia Forum. 27-32. [10] Dong, X. R. (2022). ROK presidential election and foreign policy outlook of Yoon Suk-yeol administration. Contemporary World. (04), 50-55. [11] Kurata, H. (2019). Korean peace building and Sino-US relations: An "Ad-hoc" concert of interests? Journal of Contemporary East Asia Studies, 8(1), 30-49. [12] Yangmo, K. (2019). Privatized foreign policy? explaining the Park Geun-hye administration’ s decision- making process. Korea Journal, 59(1), 106-134. [13] Shin, S. (2020). The rise and fall of Park Geun-hye: The perils of South Korea's weak party system. Pacific Review, 33(1), 153-183. BCP Social Sciences & Humanities HASS 2022 Volume 18 (2022) 399 [14] Hahm, S., & Heo, U. (2020). President Moon Jae-in at midterm: What affects public support for Moon Jae-in? Journal of Asian and African Studies (Leiden), 55(8), 1128-1142. [15] Azad, S. (2022). Perks and perils of strategic choice: South Korea's Iran policy under Moon Jae-in. East Asia (Piscataway, N.J.), 1-17 1. Introduction 2. Neoclassical Realism Theory and Formulation of South Korea’s Foreign Policy 2.1 Overview of Neoclassical Realism Theory 2.2 System Pressure Faced by South Korea and Domestic Factors Affecting Decision-Making 3. Policy Analysis of Park Geun-hye Administration's Deployment of THAAD 3.1 Analysis of Reasons for the Deployment of THAAD by the Park Geun-hye Administration 3.1.1. Park Geun-hye's Personal Attitudes 3.1.2. Conservative Strategic Culture 3.1.3. State-Society Relations During the Park Geun-hye Period 3.1.4. Overview of Congress During Park Geun-hye Period 3.2 Impact of the Park Geun-hye Administration's Foreign Policy 4. Analysis of the Moon Jae-in Administration's Policy towards THAAD 4.1 Reasons for the Moon Jae-in Administration’s "Three Noes" Commitment 4.1.1. Moon Jae-in's Personal Attitudes 4.1.2. Progressive Strategic Culture 4.1.3. State-Society Relations During Moon Jae-in Period 4.2 Diplomatic Autonomy of the Moon Jae-in Administration and Hedging between China and the United States 5. Comparison between Park Geun-hye Administration and Moon Jae-in Administration on THAAD Issue 6. Prospects of Yoon Suk-yeol’s Foreign Policy after Taking Office 6.1 System Pressure and Factors of North Korea Faced by Yoon Suk-yeol Administration 6.2 Some Statements of Yoon Suk-yeol’s Administration on Foreign Relations 6.2.1. Rebuild the ROK-US Alliance and Strengthen the All-round Strategic Alliance 6.2.2. Develop Mutually Respectful ROK-Sino Relations 6.2.3. Build a Future-oriented ROK-Japan Relations 6.2.4. Always Be Open to the Dialogue with North Korea and Get Ready to Respond to Any Provocation by North Korea 6.3 Trend of South Korea's Foreign Policy Under Yoon Suk-yeol’s Administration 7. Conclusion References