A Nuclear Weapon Free Zone in Northeast Asia: Prospects and Insights from Other Regions

ABSTRACT Building upon my book, “Nuclear Weapons Free Zones”, I assess the scope conditions for a Nuclear-Weapon-Free Zone (NWFZ) in Northeast Asia. In particular, I evaluate the role of the value of common security for states as a way to cope with nuclear threats, regional economic cooperation, regional institutions, democracy, regional powers, and nonproliferation entrepreneurship. In addition, I offer insights from other regions. While the existing conditions in the Northeast are not currently conducive for a NWFZ, Northeast Asia’s effort should be put into achieving the end of the DPRK nuclear program, the Denuclearization of the Korean Peninsula, and perhaps at a later stage, an NWFZ might be considered.

of common security for states as a way to cope with nuclear threats, the role of regional economic cooperation, regional institutions, democracy, regional powers, and nonproliferation entrepreneurship. In addition, I offer some insights from other regions.

Value of Common Security
As mentioned in the introduction, a NWFZ in Northeast Asia would consist of actors with different approaches to nuclear weapons. The ROK and Japan are nuclear threshold states; the DPRK is a nuclear-armed state that withdrew from the NPT, and China is a nuclear-weapon state under the NPT. The United States, Russia, and China (along with the other nuclear weapons states) will need to bestow negative security assurances towards the countries of a potential NWFZ in Northeast Asia. However, China's place in the region and role as patron of the DPRK makes it part of the actors that would negotiate a would-be NWFZ. In other words, China's role would be beyond granting negative security assurances.
China entered the nuclear club in 1964 and became the world's fifth nuclear-weapon state under the NPT. Currently, the Chinese nuclear stockpile is the third largest in the world after the United States and Russia. According to the Nuclear Threat Initiative (NTI), China has 320 nuclear warheads, 280 intercontinental ballistic missiles (ICBMs), 72 submarine-launched ballistic missiles (SLBMs), and 20 gravity bombs (Nuclear Threat Initiative n.d.). The central pillar of its nuclear doctrine is the "no first use" policy by which China pledged not to use nuclear weapons against states without nuclear weapons. During the last decade, China has heavily invested in modernizing its nuclear weapons system, particularly its strategic missile forces and nuclear submarine fleet (Yuan 2014, 509). It is expected that China will increase its nuclear stockpile by 2030. Hence, it does not seem China will reduce its nuclear stockpile when nuclear reductions talks have stalled internationally.
While China has historically supported NWFZs, partly due to its "no first use" policy, its backing for a Northeast Asian NWFZ is not evident. There are several reasons behind China's apparent reluctance (Koo 1998, 134-135). First, China's regional security needs do not seem to be advanced by an NWFZ because the regional security scenario is favorable for its interest. China's regional power is growing and will not be contested by regional states. That means that the ROK and Japan will continue to base their security on the US security umbrella. Second, negative security assurances, which China would have to commit, would need an understanding between Russia, China, and the United States. That outcome does not seem to be attainable soon. Third, another barrier against an NWFZ from the Chinese perspective is the potential Japanese nuclearization. Fourth, while an NWFZ in Northeast Asia won't change China's nuclear status, it might put some limits on missile deployment. Notwithstanding China's scant incentives for supporting an NWFZ, China was the leading supporter of the Six-Party Talks in the past and is still its leading proponent (Wan 2018, 63). This means that the denuclearization of the Korean Peninsula seems to be the preferable security arrangement for the region, from the Chinese perspective, rather than a NWFZ.
In the case of the ROK, especially after the end of the Korean War, the country became dependent on US military support (Snyder and Easley 2014, 448) that consisted of the deployment of troops on ROK soil, conventional arms supply, and deployment of tactical nuclear weapons (withdrawn in 1991). Still today, the ROK is under the US nuclear umbrella as the country is the United States' vital partner, along with Japan, in Northeast Asia. Despite the reliance on US security guarantees, the alliance did not prevent the ROK from seeking nuclear weapons. The ROK flirted with nuclear weapons in the 1970s when the longtime dictator Park Chung-hee initiated a clandestine nuclear weapons program that included the development of long-range missiles amid the fear of abandonment by the United States and the DPRK threat (Taliaferro, 2019: 160-210). Under heavy pressure from the United States, however, Park capitulated and terminated the clandestine program in 1976. While the United States hindered the ROK's attempts to pursue nuclear weapons, the country could develop an extensive atomic infrastructure that allowed it to become a key exporter of nuclear technology in our time (Kane, Lieggi, and Pomper 2011). Nowadays, the ROK is in good standing with the nonproliferation regime, and its immediate goal is to achieve the denuclearization of the Korean Peninsula, as the first step toward a future NWFZ (Koo 1998, 136-137), which it committed itself to in 1992.
As a consequence of its defeat in World War II, Japan was occupied by the United States, and its reintegration into the international community had to wait until 1951 with the signing of the Treaty of San Francisco and the US-Japan Security Treaty (Hughes 2014, 375). Japanese reintegration into the international community under the US security aegis meant that Japan would receive US aid and get access to the US market. This strategy allowed Japan to dissipate fear of rearmament among its neighbors and let it focus on economic development. These principles were embedded in the so-called Yoshida Doctrine -after Prime Minister Shigeru Yoshida (1946-1947 and 1948-1954) (Hughes 2014, 374-375), who established Japan's grand strategy: reliance on US security guarantees and a minimal investment in defense, including the avoidance of military intervention abroad. Japan's dependence on US security protection was upgraded with the so-called nuclear-extended deterrent after China tested its first nuclear device. By this time, there was a belief that if China joined the nuclear club, Japan and other countries would follow suit soon after. The United States' preferred policy option was to interpret the US-Japan Mutual Security Treaty so that the United States would protect Japan even with nuclear weapons to discourage it from pursuing the nuclear option. These assurances were issued by President Johnson to Prime Minister Satō in 1965 1 and have been known since then as the US guarantee of an extended nuclear deterrence whose validity still stands (Hoey 2016, 490). Two years after Japan's formal inclusion under the US nuclear umbrella, Japan's nonproliferation commitment was embedded in the so-called Three Non-Nuclear Principles. In 1967, Prime Minister Satō spoke before the Japanese Parliament and stressed that Japan would not produce, possess, or permit the introduction of nuclear weapons. Since then, the Three Non-Nuclear Principles (Hoey 2016, 491) have represented Japan's bona fides on this matter. While some domestic opposition to forgo the nuclear option existed in Japan then, the country eventually ratified the NPT in 1976.
Japan's main threats are both China and the DPRK (Debs and Monteiro 2018, 108). The traditional fear of China has not been assuaged since China has been modernizing its military capabilities and has been more assertive around its maritime claims in the last two decades. The DPRK's ballistic missile capabilities with nuclear warheads can reach Japanese coasts and the mainland. Beyond Northeast Asia, Japan's security concerns have been of relatively low importance (Hughes 2014, 378). Japan is considered a nuclear threshold state because of its extensive atomic infrastructure and ability to manage the entire nuclear fuel cycle (Rublee 2012). Therefore, Japan has the material and technological know-how to produce a nuclear bomb in a very short time span (Debs and Monteiro 2018, 107).
The DPRK is a communist hereditary dictatorship created by Kim Il-sun, who ruled the country from its creation in 1948 until his passing in 1994. Since 2011, it has been led by Kim Jong-un, the grandchild of the dynasty founder. Nowadays, the DPRK is an isolated country with few friends and a stagnating economy (Delury and Moon 2014, 440). The DPRK has a vast weapons of mass destruction program that includes a nuclear arsenal and chemical and biological weapons capabilities. In 2006, the DPRK tested its first nuclear weapon, and in 2017 tested its first ICBM. Estimates indicate that the DPRK possesses between 30 and 40 nuclear weapons and ballistic missiles of short and medium range (Hamel-Green 2021, 208). It is expected that the DPRK, in the absence of negotiations or agreements, will continue increasing its nuclear stockpile. So far, it has conducted six nuclear tests and continuously tests missiles that reach Japan's coastline.
The DPRK's nuclear weapons program poses many challenges to Northeast Asia's security (Shifrinson 2019, 27-28). First, it is a direct threat to the ROK and Japan. Second, it represents an entrapment risk since the clash between the two Koreas can push the United States and China to intervene. Third, DPRK nuclear proliferation might impact Japanese and the ROK calculus on acquiring nuclear weapons (Debs and Monteiro 2018, 110). As the DPRK's top priority is maintaining sovereignty and regime survival amid US threats and enmity, the DPRK does not believe that regional security regimes can ensure its security. Hence, it pursued a strategy of procuring deterrence capabilities in both conventional and nuclear domains (Delury and Moon 2014, 434). The repetition of its commitment to the Denuclearization of the Korean Peninsula is a strategy to buy time as the DPRK has established itself as a nuclear weapons state, and there is no prospect that, in the mid-term (Shifrinson 2019, 37), the country would roll back its nuclear program under either a NWFZ or a Korean Peninsula Denuclearization agreement.
The United States has a robust military presence in the region (Hamel-Green 2021, 209): air and naval bases in Japan, the ROK, Guam, Hawaii, Micronesia, and Australia. In addition, its nuclear missiles can reach any point in either the DPRK or China. In terms of operational warheads, the United States possesses around 3,800 nuclear weapons. US submarines patrol the South China Sea and the waters of the Korean Peninsula. In Russia's territories in Northeast Asia, there is a nuclear submarine base, and its missiles can reach every point in the region. Russia has conducted military exercises (Hamel-Green 2021, 213), with China, in the East China Sea, the Sea of Japan, and the South China Sea over the last decade.
In sum, a shared belief in common security is lacking in Northeast Asia (Sajima 1998, 141) as several factors constrain an NWFZ in the region. First, Japan and the ROK have pledged to maintain their denuclearized status despite the threats from the DPRK. They continue to rely on the US nuclear umbrella for their defense, however, and no relevant domestic actors nowadays suggest the end of that support. Second, the United States is reluctant to consider an NWFZ because its influence would be reduced by removing the nuclear umbrella provided to the ROK and Japan (Koo 1998, 134). Third, Japan's and the ROK's status as nuclear threshold states would be hindered by an NWFZ as it would constrain much of their nuclear development (Koo 1998, 135) related to the fuel cycle and reprocessing technologies. Fourth, as previously underlined, China is not enthusiastic about an NWFZ, as its nuclear strategy toward its immediate neighborhood would be affected (Koo 1998, 134-135). Fifth, the DPRK's nuclear trajectory does not seem to be reverting anytime soon, and without a disarmed DPRK, an NWFZ cannot be achieved. Sixth, so far, Northeast Asia countries have not been supporters of multilateral security (Cha 2014, 741) as they have not invested in building regional security architectures in fields other than arms control. Instead, they chose to deal with security matters through the prism of security self-reliance and, in the case of Japan and the ROK, the alliance with the United States. Seventh, through a NWFZ, nuclear weapons states would give negative security assurances to the region's actors. Therefore, a NWFZ would need an understanding between Russia, China, and the United States. The actual conditions are not conducive to a strategic dialogue between the most significant nuclear powers. Russia's invasion of Ukraine has jeopardized its ties with the United States, and the existing antagonism will not be reduced anytime soon. Concerning China -US ties, the prevailing mood in Washington is of caution toward Beijing, and a nuclear understanding between both countries should not be expected anytime soon either. Last but not least, no official dialogue on the NWFZ in Northeast Asia precludes any possibility of advancing the idea (Wan 2018, 75). This attests to the idea that a NWFZ has not gained much interest in policymaking and diplomatic circles.
While Northeast Asian actors do not believe that a NWFZ is the best way to deal with their security concerns and the security conditions for such an outcome are not ripe (Wan 2018, 76), Northeast Asia's effort should be put into achieving the end of the DPRK's nuclear program, the denuclearization of the Korean Peninsula and, perhaps in a later stage, an NWFZ might be considered. In this regard, the denuclearization of the Korean Peninsula represents a shared consensus between China, the ROK, and Japan. This case would resemble the experience of Argentina and Brazil. They solved their nuclear dispute through the "denuclearization of the Southern Cone". Later, they fully ratified the Tlatelolco Treaty (the Latin American NWFZ) and finally joined the NPT.

Regional Institutions
Regionalism in Northeast Asia emerged late in comparison with other regions and unsolved disputes and memories from the past have put a barrier in the path of integration of its core state members: the ROK and China are among the Asian countries with the most negative attitudes toward Japan (Inoguchi 2011, 234). Northeast Asia is far from being either a zone of peace or a security community since interstate war is an actual possibility. However, from an optimistic perspective, regional cooperation in Northeast Asia has steadily increased in the last 20 years. This cooperation is based on the premise of functionalism: collaboration is built upon issue areas and grows over time.
Cooperation in Northeast Asia has been taking place in areas such as the environment, finances, and logistics (Yoshimatsu 2010, 248).
The financial crisis that shocked Southeast Asia and much of the world economy in 1997 represented a turning point for Asian regionalism. The ASEAN+3-consisting of the ten ASEAN Member States and China, Japan, and the ROK -convened for the first time that year to deal with the impact of the crisis. The effect of the crisis forced regional states to coordinate actions. The ASEAN+3 promoted the Chiang Mai Initiative (Nesadurai 2014, 236)-a bilateral currency swap system -to ease the region's shortterm liquidity difficulties. The evolution of the ASEAN+3 group also nurtured the creation of the East Asia Summit (ASEAN+6), which was first convened in 2005.
In 1999, during the ASEAN+3 meeting, the three leaders of China, ROK, and Japan met for the first time in the modern era, albeit in an informal venue (a breakfast) (Yoshimatsu 2010, 253). Since then, the three leaders began to meet regularly, and in 2003 they issued -still within ASEAN+3-the Joint Declaration on the Promotion of Tripartite Cooperation among China, Japan, and the ROK. In 2008, the first trilateral meeting outside that framework was held (Yoshimatsu 2010, 254). A few years later, in 2011, the TCS was established as the only regional organization for China, Japan, and the ROK. Trilateral ministerial meetings also complemented this process, as ministers of the three countries have been meeting regularly since the late 1990s.
As the financial crisis of 1997 triggered the ASEAN+3 meetings, the nuclear crisis caused by the DPRK's NPT withdrawal paved the way for the Six-Party Talks. In other words, the 2003 crisis created the demand for a regional solution to the DPRK problem. Likewise, the Six-Party Talks corroborated the need for regional institutions to advance either NWFZs or nonproliferation initiatives. The fact that the first regionalism initiatives were created a few years before -ASEAN+3 and the trilateral meetings within that framework -proves that regional organizations and forums serve to socialize their members, deepen the personal ties between leaders, create confidence, and promote cooperation in different areas. In Northeast Asia, the evolution of the ASEAN+3 spilled over to the Six-Party Talks. Therefore, for a NWFZ to succeed, it would need the participation of all Northeast countries, including the DPRK, in regional organizations over time.

Regional Economic Cooperation
As of 2022, China and Japan are the second and third-largest economies after the United States, and the ROK is ranked tenth. The economic preponderance of this region might be attributed to factors such as being a global manufacturing center that produces goods and services efficiently and cheaply. Most of the countries were able to pursue export-oriented strategies and achieve high degrees of trade liberalization. Asia's economy also witnessed the expansion of multinational companies from core states and the creation of companies and brands that became transnational (Dent 2014, 264). Economic interdependence in Asia was pushed forward by Japan's production networks in the 1980s and 1990s and China's rise since the 1990s (Yeo 2018, 164). A common denominator across the three countries is that they adopted neoliberal reforms in the 1990s, including the privatization of public assets, the reduction of trade barriers, and the deregulating of markets (Yoshimatsu 2010, 257). Intraregional trade between the three core states has increased in the last decades from 12.3% to 19% but is still lower than other trade blocks such as ASEAN, the European Union, or the North American Free Trade Agreement (NAFTA) (Park 2017, 116).
Northeast countries such as Japan and the ROK in the 1990s were reluctant to sign Free Trade Agreements (FTAs) because they preferred multilateral frameworks such as the General Agreement on Tariffs and Trade (GATT) to liberalize their trade. This choice would be changed after the financial crisis of 1997 that led ROK and Japan to propose the signing of FTA (Dent 2014, 277). Free trade negotiations between China, the ROK, and Japan were kicked off in 2012, and after many negotiation rounds, a breakthrough is not in sight. For their part, China and the ROK signed an FTA in 2015, and Northeast Asian countries signed Preferential Trade Arrangements (PTAs) and other economic cooperation agreements with Southeast Asian nations. Scholars such as John Ravenhill (Ravenhill 2010, 200) state that interdependence has not resulted in the creation of regional economic institutions in Northeast Asia, and that there is no correlation between the PTAs and the increment of trade and investment flows. In other words, PTAs serve a political function, namely, strengthening diplomatic relations between trade partners and serving as a competition tool for economic leadership between China and Japan. For his part, Yoshimatsu argues that economic interdependence (Yoshimatsu 2014, 569) is a condition for institutionalization in Asia, although its effectiveness in easing security tensions has been limited. In the case of Northeast Asian countries, Yoshimatsu explains, the summits between the three states could not effectively deal with the DPRK nuclear question.
Indeed, economic interdependence in Northeast Asia was achieved without economic institutions (Park 2017, 111), and it has not solved all security issues, including the DPRK's nuclearization. However, economic interdependence creates positive incentives for, if not alleviating tensions, at least for containing them. The deep economic ties between the core states would be jeopardized in case of direct conflicts. While the FTA agreement has yet to be concluded between the ROK, Japan, and China, many negotiations have been held since 2013 (Park 2017, 114). Ongoing negotiations improve the regional environment by assuming a cooperative vocation among the parties. Such is the case that ASEAN+3 launched the Chiang Mai Initiative, a regional financial instrument, and later on, this collaborative environment created the conditions for the Six-Party Talks. In the case of the DPRK, the lack of economic cooperation with the ROK and Japan and, to a lesser extent, with China reduces the incentives for cooperation in the nuclear field. The Six-Party Talks Joint Statement of 2005, which makes references to prosperity and economic cooperation, assumes a link between the eventual denuclearization of the Korean Peninsula and the DPRK's "integration" in the region. The same logic was behind the Arms Control and Regional Security (ACRS) forum and the Middle East and North Africa (MENA) conferences in the first half of the 1990s. Economic cooperation between Israel and Arab countries was seen as hand-in-hand with the discussion on arms control. The most vivid example of this link is the Argentine and Brazilian nuclear rapprochement that took place simultaneously with the first steps in their economic integration. The same can be said about the NWFZs in Latin America, the South Pacific, Southeast Asia, Africa, and Central Asia, which were established against a regional integration process. In the specific case of Northeast Asia, economic cooperation created the conditions for the Six-Party Talks but by itself was not enough for their success and persistence over time.

Democracy
In the case of Northeast Asia, the two authoritarian regimes, the DPRK and China, are nuclear weapons states. In contrast, the democratic ones, Japan and the ROK, remain committed to not proliferating. At first glance, there would be a correlation between political regime and stance on nuclear weapons in Northeast Asia. As in other regions, however, the link between democracy and nuclear weapons is difficult to assess. Indeed, the ROK pursued the nuclear option under Park's military regime, but it closed it during the same military rule, albeit under heavy pressure from the United States. In this case, neither democracy nor democratization seems to have played a significant role in the ROK's nuclear orientation. While counterfactual, an eventual collapse of the DPRK and absorption by the democratic ROK will presumably lead to its denuclearization.

Regional Powers
Northeast Asia's core states, the ROK, China, and Japan, have attributes that make them suitable to lead regional initiatives. Let's assess the extent to which these states might lead an NWFZ process.
As of 2022, the ROK's economy is ranked tenth, marking a story of successful economic development and democratization (Snyder and Easley 2014, 446-447). These two key factors allowed the country to diversify its foreign policy ties in the post-Cold War period, enhance its role in international institutions and promote multilateral cooperation (Snyder and Easley 2014, 457). The ROK is considered a minor player in the region compared to China and Japan, so it tries to compensate for its weakness vis-àvis its neighbors by adopting an active role in global governance structures and institutions. Some examples are the ROK's role in chairing the G-20 in 2010 and hosting the second Nuclear Security Summit in 2012. Moreover, the ROK engaged in initiatives for climate change: in 2008, it launched the East Asia Climate Partnership at a G-8 meeting (Shin 2016, 200). The ROK also deployed its military forces in many peacekeeping missions worldwide. As of 2022, the ROK was engaged in 12 peacekeeping operations and contributes to them with more than 85,000 people, including troops and military observers. The ROK has also developed its "soft power" across Asia as its pop culture is widely consumed. The rise of the country's profile has been epitomized by the slogan "Global Korea" (Snyder and Easley 2014, 449), coined by former president Lee-Myung-bak (2008. Furthermore, the ROK became a strong supporter of regional organizations (Hundt and Kim 2011, 251) as the country joined APEC, ARF, ASEAN+3, the Six-Party Talks, and EAS.
Despite the mentioned attempts to brand ROK as a middle power, its regional clout is somehow limited, and hence, its potential role as a regional leader is reduced. Among the factors that limit the ROK's policy options is the ongoing conflict with the DPRK (Snyder and Easley 2014, 459) and the consequent reliance on the United States to deal with the security implication of the conflict.
China and Japan are considered actors with the attributes of regional leaders. Both Japan and China account for 80% of East Asian GDP (Dent 2012, 263). While Japan was the engine of economic growth in previous decades, China is now the leading trading partner in East Asia. If the turning point for regionalism in the broad East Asia sphere was in 1997, the quest for regional leadership surged due to that process. As there is no expectation of co-leadership between Japan and China (Dent 2012, 264), both countries try to limit the other's influence in regional initiatives and enhance their clout across different areas (Dent 2012, 271).
So far, regional leadership has been played in issue areas in regional forums and ad hoc initiatives to gain followers in a subtle competition (Nabers 2010, 933). Within the ASEAN+3 framework, Japan's New Miyazawa Initiative of 1998 (Dent 2012, 271) immediately preceded the Chiang Mai Initiative. That initiative included a currency swap and credits to ease the burden of the financial crisis. Later, China exercised regional leadership by leading and hosting the Six-Party Talks. Most recently, China's Belt and Road Initiative (BRI), launched in 2013 by President Xi Jinping, took the form of ambitious infrastructure projects and investment initiatives to expand China's influence over East Asia. Japan offered its version to balance China and launched Japan's Free and Open Indo-Pacific (FOIP) to promote regional connectivity and physical infrastructure development in the Indo-Pacific area. Along the same line, Japan sponsored the Asia Energy Transition and launched the Asia Health and Wellbeing Initiative (AHWIN) to promote regional cooperation across healthcare systems in Asia. As Japan engaged in health diplomacy, China responded with its Health Silk Road. In addition, China has propelled regional FTAs as a diplomatic tool to expand its influence along with the Asian Infrastructure Investment Bank.
As previously mentioned, war memories still impact Japan's ability to exercise regional leadership in Northeast Asia, as the ROK and China are the countries that hold the most negative views of Japan in Asia. On the other hand, China's emphasis on "peaceful rise" is not always shared by regional actors that fear Chinese domination (Dent 2012, 273). For that reason, Asian actors other than the ROK and Japan support a strong US security presence in Asia (Aggarwal and Koo 2014, 715).
As East Asian and Northeast Asian regionalism is in the making, the contest for leadership between China and Japan is open, and it has clear implications for a potential NWFZ. In contrast to other regions where a pair of regional powers promoted NWFZs, Northeast Asia core states have yet to go the extra mile by proposing an NWFZ. Establishing these regimes requires the cooperation of two regional powers when there are more than one. In the case of the Latin American Tlatelolco Treaty, Brazil and Mexico were their leading supporters. In the case of Africa, both Nigeria and South Africa were the leading states that brought to an end the negotiation of the Pelindaba Treaty. The South Pacific and Central Asia cases are similar; the NWFZ in these regions counted on the leadership of states such as Australia, New Zealand, Kazakhstan, and Uzbekistan, respectively. Even the Brazilian-Argentine Agency for Accounting and Control of Nuclear Materials (ABACC) benefited from the rapprochement of the two core states of the Southern Cone.
The Six-Party Talks allow a comparison with the ACRS talks in the Middle East in the early 1990s, which also ended abruptly. During the ACRS rounds, the core states -Egypt and Israel -had different concepts of where those talks should have led. The open disagreements between Israel and Egypt derailed the discussions and led to the end of the ACRS talks. In the case of the Six-Party Talks, Japan and China competed and clashed. China became the leading voice at the Six-Party Talks by bringing the DPRK to the negotiation table, easing the bilateral talks between the United States and the DPRK, and hosting the discussions. China's strategy at the Six-Party Talks was improving its relationship with the United States and enhancing its international image as a responsible rising power. By contrast, Japan adopted a less proactive approach than China and a hawkish position toward the DPRK, more aligned with US hardliners (Lee 2010, 136). In short, the zero-sum game between China and Japan precludes the possibility of advancing a NWFZ in Northeast Asia, which would require strong cooperation between the core regional powers.

Nonproliferation Entrepreneurship
As Asia is the region that has more nuclear armed states, regional actors regard nonproliferation norms differently. In the case of Northeast Asia, that should not come as a surprise since it includes two nuclear armed states, one recognized by the NPT and one that withdrew from it, and it has two states with a sizable nuclear infrastructure that put them close to the nuclear bomb (if they would want to pursue that path).
For its part, Japanese nuclear facilities are under IAEA safeguards, including the strictest inspection regime regulated by the Additional Protocol. Although Japan has faced a threatening environment, it has upheld nonproliferation norms constantly and systematically since the Three Non-Nuclear Principles were issued by Prime Minister Satō in 1967. Maria Rost Rublee, who has extensively studied Japan's nonproliferation approach, has made several salient points about it (Rublee 2012, 160-162). First, the Japanese's reliance on the US nuclear umbrella limits its "scope of assertiveness" on nuclear disarmament diplomacy. Second, Rost Rublee underscores that Japanese leadership in disarmament diplomacy is less confrontational toward nuclear weapons states and focused on creating spaces for dialogue in this matter. In this regard, Rost Rublee highlights the many initiatives Japan supports: Japan has sponsored study visits to Hiroshima and Nagasaki; it has hosted the annual Asian Export Control Seminar since 1993; the Asian talks on nonproliferation and IAEA conferences on nuclear security, among other initiatives. Japan also funded concrete nonproliferation measures. In the 1990s, Japan provided funds to the Korean Peninsula Energy Development Organization to transfer light water to DPRK reactors. In another high-profile investment, Japan supported the former Soviet republics in getting rid of their nuclear weapons infrastructure and Russia's disposal of weapons-grade plutonium; it also funded CTBT (Comprehensive Nuclear-Test-Ban Treaty) technical activities and the negotiations toward the Central Asian NWFZ. Third, Rost Rublee notes that Japan's core nuclear diplomacy is based on remembering the horror of the nuclear attacks in 1945. Fourth, Japan is the only non-nuclear weapons state with reprocessing capabilities for civilian use. While Japan is in good standing with the nonproliferation regime, the main risk is the precedent set for other countries that would be tempted to pursue reprocessing technologies and other fuel cycle parts upon the Japanese experience. The country had a small reprocessing plant in Tōkai (World Nuclear News 2014) that ceased its operations in 2007, and it has been working on the Rokkasho Nuclear Fuel Reprocessing Plant (Rublee 2012, 163). Its entry into operation was postponed many times. Once in operation, that facility will produce 800 tons of spent fuel per year. In addition to the precedent the Rokkasho Plant sets, it poses a nonproliferation risk: plutonium reprocessing would strengthen Japan's latency by increasing its fissile materials.
China is a latecomer to the nonproliferation regime. China's nuclear program began in 1957 with the assistance of the Soviet Union (Zhu 1997, 41). It eventually became a nuclear-weapon state when it tested its first nuclear bomb in 1964. Shortly after becoming a nuclear state, China adopted its main contribution to nonproliferation, the "no first use" principle (Zhu, 1997, 44) by which it pledged not to use or threaten to use nuclear weapons against non-nuclear-weapon states. However, China's inclusion into the nonproliferation regime would have to wait. China was critical of the NPT, highlighting that it was a discriminatory treaty, and rejected the Limited Test Ban Treaty.
A significant step to join the regime was taken in 1984 when China joined the IAEA. Following that, China signed a voluntary safeguards agreement with the agency and shared a list of civilian facilities that were placed under safeguards. In the early 1990s, the relationship with the IAEA was upgraded, and China started informing the agency about its import and export of nuclear materials. In 1990, China attended, as an observer, the Fourth NPT Review Conference, and two years later, after many years of opposition, China acceded to the NPT in 1992. In 1995, as a full member of the NPT (Zhu 1997, 45), China supported the treaty's extension. China (Fey et al. 2013, 181) also joined the Nuclear Suppliers Group and implemented domestic legislation related to export control. China halted its testing program in 1996, but it has not taken the extra step of acceding to the CTBT. China also ratified the CWC in 1997.
China has been a supporter of NWFZs since it was the first nuclear weapons country to sign Protocol 2 of the Tlatelolco Treaty (Zhu 1997, 43). Later on, it ratified the protocols of the Pelindaba Treaty, the Rarotonga Treaty, and the Semipalatinsk Treaty. In 2021, at the ASEAN summit, China's President Xi Jinping (Musto 2021) announced that China was prepared to sign the protocol of the Bangkok Treaty that nuclear weapons states have disputed to this day.
While China has evolved in terms of its support of the nonproliferation regime, it has supplied nuclear technology to several countries that have since developed nuclear weapons programs including Pakistan (Khan 2012), Iran (Gerardi and Aharinejad 1995), and Algeria (Albright and Hinderstein 2001), among other proliferating countries (Yuan 2014, 517).
The DPRK joined the NPT in 1985 and concluded a safeguard agreement with the IAEA in 1992. Regarding other nonproliferation agreements, it signed the Biological Weapons Convention (BWC) in 1987 and the Geneva Protocol in 1989, but it has not joined either the CTBT or the CWC (Chemical Weapons Convention). Due to the IAEA inspections performed in 1992, it was determined that the DPRK had produced weaponsgrade plutonium. That discovery triggered a crisis that paved the way for the Agreed Framework with the United States by which the DPRK was going to freeze its nuclear program in exchange for humanitarian assistance. The Agreed Framework was terminated in 2002 when the DPRK admitted it was embarking on a uranium enrichment program (Wunderlich et al. 2013, 274). In 2003, the DPRK became the first and only country to withdraw from the NPT. Like China in the past, the DPRK still regards the NPT as a discriminatory instrument (Wunderlich et al. 2013, 276).
While the DPRK signed the Joint Declaration of the Denuclearization of the Korean Peninsula and agreed to halt its nuclear weapons program, its behavior says otherwise. The nuclear tests conducted by the DPRK attest to the country's determination to continue the nuclear path. The nuclear tests also changed the logic of the previous negotiation attempts, such as the Six-Party Talks. Instead of preventive diplomacy, a framework for disarmament is now needed (Wunderlich et al. 2013, 275). In the case of the DPRK agreeing to its denuclearization, the path to its realization will be full of obstacles. A comprehensive verification and inspection regime would be at odds with the DPRK's polity, whose authoritarian nature precludes any transparency measure (Wunderlich et al. 2013, 279).
The DPRK assisted other countries, such as Syria and Iran, in advancing clandestine nuclear programs. In the case of Syria, after Israel's raid that destroyed the reactor of Dair Alzour, it was revealed that the reactor was built with DPRK assistance (Kimball 2008) and that ten scientists from that country were killed in the bombing operation.
The ROK pursued a nuclear weapons program in the 1970s that was halted under pressure from the United States. In 1975, it ratified the NPT and adopted the IAEA safeguards. In 1992, the ROK signed the Joint Declaration of the Denuclearization of the Korean Peninsula with the DPRK and abided by it even though its northern neighbor abrogated its commitment. Since 2004, the ROK has in force the Additional Protocol, which prompted an IAEA investigation after the country failed to report undeclared experiments carried out by the Korea Atomic Energy Research Institute. These experiments involved the separation of plutonium and uranium enrichment. While the amount of nuclear material produced was small, the IAEA expressed its concern and launched an investigation. Consequently, the ROK strengthened its supervision over nuclear activities (Kane, Lieggi, and Pomper 2011, 23).
The ROK became an exporter of nuclear technology and a key actor in this sector in the Middle East region (Kane, Lieggi, and Pomper 2011, 22). The Korean Atomic Energy Research Institute built the first research reactor in Jordan, inaugurated in 2016, and is building the Barakah nuclear power plant in the United Arab Emirates. Currently, the ROK is in good standing with the nonproliferation regime, which is crucial in its strategy to become a leading nuclear exporter. However, the country has not been a leader in the nonproliferation regime even though the ROK raised its profile in that field by hosting the Nuclear Security Summit in 2012 (Kane, Lieggi, and Pomper 2011, 27).
The ROK has not been enthusiastic about increasing the restrictions on the trade of fuel cycle components within the Nuclear Suppliers Group (NSG), and it has not required the Additional Protocol as a condition for being an ROK nuclear recipient. The ROK was also hesitant regarding implementing sanctions against Iran in the context of its nuclear weapons program (Kane, Lieggi, and Pomper 2011, 26). Moreover, the ROK and the United States have been working on plutonium separation for the last ten years using "pyroprocessing" technology (Kane, Lieggi, and Pomper 2011, 25). By separating plutonium, the ROK becomes a nuclear threshold state.
In sum, China, ROK, and Japan are not "norm entrepreneurs" in the nonproliferation field as they have not gone the extra mile in pushing forward regional or international nonproliferation regimes as other regional powers have. These countries have no comparable achievement to Mexico's role during the Tlatelolco Treaty, the NPT negotiations, or Australia's work toward the CTBT and the CWC. In the case of Japan and the ROK, countries in good standing with the IAEA, their status as nuclear threshold states also limit their "entrepreneurship", mainly because they master reprocessing technology. The security link with the United States also reduces the open space for Japan and ROK to play a larger role in the nonproliferation field. The extended deterrence is a stumbling block to an NWFZ in Northeast Asia because it means that the ROK and Japan depend on nuclear weapons for their security, which goes against nonproliferation principles. In the case of China, nuclear modernization focuses on long-range ballistic missiles and atomic submarine capabilities, and it is expected to increase its nuclear stockpile by the end of this decade. Although China is a supporter of NWFZs elsewhere, in the case of Northeast Asia, China has not expressed official backing.

Conclusions
Several conclusions can be drawn from the case of Northeast Asia. The countries of this region do not believe that their security can be improved by establishing regional security regimes or institutions. Such frameworks are lacking in the area: the ROK and Japan rely on US security guarantees, and all believe in security self-reliance. In other words, the regional experience is not compatible with a NWFZ. Even though there are no conditions for a NWFZ, countries have expressed support for a framework such as the Denuclearization of the Korean Peninsula. The Six-Party Talks experience, the first security forum in Northeast Asia, validates this point. Still, that framework was devised before the DPRK became a nuclear weapon state. Hence, a disarmament roadmap for the DPRK has to be developed, which is seen as a daunting task.
In the case of Northeast Asia, similarity to other regions can be found in the role of regional organizations: they had a spillover effect on security regionalism, as the Six-Party Talks show. Just six years after the creation of ASEAN+3, Northeast Asia countries gathered together to find a solution to the DPRK nuclear program, which was only possible due to the learning and experience acquired through participation in regional organizations and forums. The challenge is that the DPRK is not part of any regional organization and cannot be socialized by them. As forums and ad hoc initiatives are the preferable options for Northeast Asian countries, enhancing regional institutionalization such as TCS might contribute to creating the conditions for nonproliferation initiatives.
Related to the previous point, no regional economic institutions exist in Northeast Asia or East Asia, but cooperation initiatives in the economic and financial fields exist. In this regard, economic interdependence should not be underestimated. As Northeast Asia is an economic hub, the leaders of China, Japan, and the ROK have incentives to manage their disputes and conflicts peacefully. The DPRK's lack of economic cooperation and interdependence within the region means the country has no incentive to cooperate in other issues such as nonproliferation.
Democracy, as in other regions, is a factor whose relevance is challenging to assess. The nuclear weapons states are indeed authoritarian, and the nonnuclear states are democratic. However, the fact that the ROK abandoned its nuclear weapons program during the military regime of Park means that states can change their nuclear preferences within the same political regime. We also pointed out that an eventual absorption of the DPRK by the ROK would entail its denuclearization.
The role of regional powers is critical for establishing a NWFZ as they are the actors that can bring different states to a negotiation process. If there is more than one regional power, two core states of the region must agree to push forward a NWFZ. As the relationship between Japan and China is more competitive than cooperative, the cooperation needed for a NWFZ cannot be advanced.
In relation to nonproliferation entrepreneurship, Northeast Asia shows a mixed record. The DPRK is the only country that withdrew from the NPT and has deceived the international community for over twenty years. China is a latecomer in the nonproliferation regime compared to Japan and the ROK. China's past in assisting proliferating countries still cast a shadow on its commitment to nonproliferation norms. While in good standing with the nonproliferation regime, both Japan and the ROK are the only non-nuclear weapons states that reprocess plutonium, and they also rely on the US nuclear-extended deterrence. Overall, the countries of this region have not been norm entrepreneurs in the nonproliferation field. Not by chance, they have not officially supported an NWFZ in the area.
To conclude, establishing an NWFZ is a task that demands many years. Brazil and Argentina fully ratified the Tlatelolco Treaty after 25 years of its approval in Latin America, the region that established the first NWFZ regime. In Africa, the NWFZ was established in 1996, but the first proposal was devised in the early 1960s. The NWFZ in Southeast Asia had to wait until 1995, after it was first suggested in 1971. Promoters of an NWFZ in Northeast Asia must consider this fact. While the existing conditions in the Northeast are not currently conducive for a NWFZ, conditions may change.

Disclosure statement
No potential conflict of interest was reported by the author.

Notes on Contributor
Exequiel Lacovsky is a research associate at The Harry S. Truman Research Institute for the Advancement of Peace, the Hebrew University of Jerusalem. He is the author of "Nuclear Weapons Free Zones: A Comparative Perspective" (Routledge, 2021) and is a member of the "Panel on Peace and Security of Northeast Asia" (PSNA) supported by the Research Center for Nuclear Weapons Abolition, Nagasaki University (RECNA).