瑞典和芬蘭施行中立政策已有長遠的歷史，瑞典甚至從1814年拿破崙戰爭後開始施行至今已超過200年。然而在2022年俄烏戰爭爆發後，兩國皆迅速作出了申請北大西洋公約組織（NATO）的歷史性決策。本研究旨在探討此一重大外交決策轉向的發展歷程，以及驅動其終結長期中立政策的因素為何。
在理論上，本研究採取瓦特（Stephen M. Walt）的「威脅平衡理論」（Balance of Threat Theory）作為核心分析架構，以彌補傳統結構現實主義單純強調「權力平衡」的解釋侷限。本研究將俄羅斯的威脅具體操作化為四項指標：整體實力、攻擊能力、地理鄰近性與侵略意圖，藉此評估瑞典與芬蘭威脅感知的累積過程。
研究發現，兩國放棄中立政策並非是單一危機所驅動，而是以2008年喬治亞危機做為開端，不斷累積最終跨越閾值的結果。在物質權力方面，俄羅斯的全球權力指數雖不及蘇聯時期，但其將資源高度集中於不對稱的攻擊能力（如波羅的海的A2/AD系統），結合地理鄰近性大幅壓縮瑞芬兩國的預警時間。隨著2014年克里米亞危機與2022年俄烏戰爭的相繼爆發，徹底擊碎兩國以合作維持和平的幻想。此外，儘管面臨相似的外部結構壓力，兩國的轉向節奏卻因歷史慣性而有顯著差異。
總結而言，兩國的歷史性轉向印證了威脅平衡理論的核心主張：驅動國家結盟制衡的關鍵並非單純的客觀「權力」，而是當敵國的「攻擊能力」、「地理鄰近性」與「侵略意圖」疊加，並跨越了國家生存的安全閾值時，國家終將打破長期維持的中立慣性，轉向尋求集體防禦體系。

Sweden and Finland have a long history of practicing neutrality. Sweden, in particular, has maintained its neutrality for over 200 years since the end of the Napoleonic Wars in 1814. However, following the outbreak of the Russia-Ukraine War in 2022, both nations made the historic decision to apply for NATO membership. This study explores the evolution of this major foreign policy shift and examines the key factors that drove these countries to end their long-standing neutrality.
For the theoretical framework, this study adopts Stephen M. Walt’s “Balance of Threat Theory” to address the limitations of structural realism, which focuses solely on the balance of power. To assess how Sweden and Finland’s perception of threat accumulated over time, the study breaks down the Russian threat into four specific indicators: aggregate power, offensive power, geographical proximity, and aggressive intentions.
The findings show that the decision to abandon neutrality was not driven by a single crisis. Instead, the decision was the result of a cumulative process that began with the 2008 Georgia Crisis. In terms of material power, although Russia’s power, measured with tools such as the Global Power Index (GPI), does not match that of the Soviet era, it has concentrated its resources into offensive power, such as the A2/AD systems in the Baltic Sea region. Combined with geographical proximity, these capabilities have severely compressed the warning times for Sweden and Finland. The consecutive outbreaks of the 2014 Crimea Crisis and the 2022 Russia-Ukraine War completely shattered the two countries’ illusions of maintaining peace through cooperation. Furthermore, despite facing similar external structural pressures, the timing and rhythm of their strategic shifts showed noticeable differences due to historical experience.
In conclusion, the historic turn of both nations confirms the core argument of balance of threat theory: the key driver of alliance formation is not simply objective “power”. Instead, when an adversary’s offensive power, geographical proximity, and aggressive intentions combine to cross the critical threshold for a neutral state’s national security and survival, the state will likely deviate from its long-standing neutrality and turn to a collective defense system.

一、 中文部分
（一） 專書
丘宏達，現代國際法，修訂3版（臺北：三民書局股份有限公司，2012年）。
丘宏達，現代國際法，修訂4版（臺北：三民書局股份有限公司，2021年）。
徐昕、郝望、李保平譯，Hans J. Morgenthau 著，國家間政治，第七版（北京：北京大學出版社，2005）。
秦亞青譯，E.H. Carr 著，二十年危機（1919-1939），第一版（北京：世界知識出版社，2005）。
閻學通、孫學峰，國際關係研究實用方法（北京：人民出版社，2001年）。
（二） 期刊論文
石之瑜，「現實主義國際政治學的知識脈絡」，問題與研究，第39卷第7期(2000年7月)，頁37-53。
施正鋒，「中立國的概念、理論、以及實務」，台灣國際研究季刊，第11卷第3期(2015年9月)，頁1-22。
張凱銘，「川普政府時期的美國國家網路戰略之研究：從威脅平衡理論分析」，遠景基金會季刊，第21卷第1期（2020年1月），頁107-170。
張凱銘，「柔性平衡理論之研究」，問題與研究，第54卷第2期（2015年6月），頁101-123。
陳麒安，「重新檢視瓦特的聯盟理論」，問題與研究，第53卷第3期(2014年9月)，頁87-115。
黃奕婷、張登及，「冷戰後韓美同盟變遷之研究（1992-2013）」，遠景基金會季刊，第18卷第4期（2017年10月），頁61-112。
楊三億，「為什麼不中立了？從關鍵時刻、地緣政治與決策模式分析瑞典與芬蘭中立政策調整」，問題與研究，第63卷第1期（2024年3月），頁55-101。
閻亢宗、賴元斌，「馬基維利的國際現實主義：兼論弱國的外交抉擇」，康大學報，第13期（2023年6月），頁17-34。
譚偉恩，「權力平衡理論之研究：現實主義的觀點」，國際關係學報，第22期（2006年7月），頁129-165。
魏百谷，「小國與強鄰相處之道－以芬蘭與俄羅斯關係為例」，台灣國際研究季刊，第6卷第1期（2010年3月），頁95-116。
蕭琇安，「轉變國際秩序下「中立」概念之地位」，問題與研究，第47卷第1期（2008年3月），頁29-54。
（三） 書籍專章
李俊毅，「重探中立概念的政治性：瑞典與芬蘭之比較」，收於吳玉山、楊三億主編，中小型國家在兩強間的抉擇（台北：奇異果創新股份有限公司出版，2019年）。
（四） 學位論文
陳芃叡，「川普政府對中遏制政策之形成：威脅平衡理論之觀點」，國立政治大學外交學系碩士論文（2021年）。
黃景徽，「俄羅斯國家安全戰略之研析：從克里米亞危機到俄烏戰爭」，國立中興大學國際政治研究所碩士論文（2023年）。
黃國明，「俄烏戰爭下瑞典與北約安全互動關係之研究-從手勢現實主義的『權力平衡』解析」，淡江大學國際事務與戰略研究所在職專班碩士論文（2023年）。
二、 英文部分
（一） 專書
Cottey, Andrew ed., The European Neutrals and NATO: Non-Alignment, Partnership, Membership? (New York: Palgrave Macmillan, 2017).
Czarny, Ryszard M., Sweden: From Neutrality to International Solidarity (Cham: Springer International Publishing, 2018).
Frear, Thomas, Łukasz Kulesa, and Ian Kearns, Dangerous Brinkmanship: Close Military Encounters Between Russia and the West in 2014 (London: European Leadership Network, 2014).
Karsh, Efraim, Neutrality and Small States, 1st Edition (London: Routledge, 2012).
Morgenthau, Hans J., Politics Among Nations: The Struggle for Power and Peace (New York: Alfred A. Knopf, 1949).
Thucydides, History of the Peloponnesian War (New York: Modern Library, Random House, 1951).
Walt, Stephen M., The Origins of Alliances (Ithaca, NY: Cornell University Press, 1987).
Waltz, Kenneth N., Theory of International Politics (New York: McGraw-Hill, Inc., 1979).
（二） 期刊論文
Arter, David, “From Finlandisation and post-Finlandisation to the end of Finlandisation? Finland’s road to a NATO application,” European Security, Vol. 32, No. 2 (2023), pp. 171-189.
Aunesluoma, Juhana and Rainio-Niemi, Johanna, “Neutrality as Identity? Finland’s Quest for Security in the Cold War,” Journal of Cold War Studies, Vol. 18, No. 4 (Fall 2016), pp. 51-78.
Beyer, Jessica L. and Hofmann, Stephanie C., “Varieties of neutrality: Norm revision and decline,” Cooperation and Conflict, Vol. 46, No. 3 (September 2011), pp. 285-311.
Bock, Andreas M., Henneberg, Ingo and Plank, Friedrich “If you compress the spring, it will snap back hard: The Ukrainian crisis and the balance of threat theory,” International Journal, Vol. 70, No. 1 (March 2015), pp. 101-109.
Cotta, Filippo Alberto, “The Evolution of Finnish-Russian Relations from 1917 to the Present,” Il Politico, Vol. 87, No. 2(July 2022), pp. 110-129.
Cottey, Andrew, “The European Neutrals and NATO: Ambiguous Partnership,” Contemporary Security Policy, Vol. 34, No. 3 (November 2013), pp. 446-472.
Dalsjö, Robert, “The hidden rationality of Sweden’s policy of neutrality during the Cold War,” Cold War History, Vol. 14, No. 2(2014), pp. 175-194.
Dahl, Ann-Sofie, “Partner number one or NATO ally twenty-nine? Sweden and NATO post-Libya,” NATO Defense College, No. 82(September 2012), pp. 1-12.
Forsberg, Tuomas, “Four rounds of the Finnish NATO debate,” Nordic Review of International Studies, Vol. 1, No. 1 (June 1, 2023), pp. 41-50.
Forsberg, Tuomas, “Bottom‐up foreign policy? Finland, NATO and public opinion,” Scandinavian Political Studies, Vol. 47, No. 3 (September 2024), pp. 283-307.
Gerring, John, “What Is a Case Study and What Is It Good for?,” The American Political Science Review, Vol. 98, No. 2(May 2004), pp. 341-354.
Gilli, Andrea, Gilli, Mauro, and Grgić, Gorana, “NATO, multi-domain operations and the future of the Atlantic Alliance,” Comparative Strategy, Vol. 44, No. 1 (2025), pp. 73-91.
Jašić, Marin, “Finland’s Cold War Neutrality: A Soviet Perspective,” Polemos, Vol. 27, No. 1 (2024), pp. 95-112.
Kim, Hyung Min, “Comparing Measures of National Power,” International Political Science Review, Vol. 31, No. 4 (September 2010), pp. 405-427.
Kunz, Barbara, “Sweden’s NATO Workaround: Swedish security and defense policy against the backdrop of Russian revisionism,” Focus stratégique, No. 64 (November 2015), pp. 1-47.
Kaarkoski, Miina, Häkkinen, Teemu, and Kilpeläinen, Helena, “Suomen Nato-jäsenyyden legitimointi menneisyyttä koskevien käsitysten näkökulmasta,” Kosmopolis, Vol. 54, No. 3 (2024), pp. 29-48.
Legucka, Agnieszka, “Russia on NATO Enlargement to Sweden and Finland,” PISM Bulletin, No. 110 ( July 8, 2022), pp. 1-2.
Palosaari, Teemu, “Still a Physician rather than a Judge? The Post-Cold War Foreign and Security Policy of Finland,” Swiss Political Science Review, Vol. 19, No. 3 (September 2013), pp. 357-375.
Pietkiewicz, Michał, “The Military Doctrine of the Russian Federation,” Polish Political Science Yearbook, Vol. 47, No. 3 (2018), pp. 506-514.
Petersson, Magnus, “The Scandinavian Triangle: Danish-Norwegian Swedish military intelligence cooperation and Swedish security policy during the first part of the Cold War,” Journal of Strategic Studies, Vol. 29, No. 4 (August 2006), pp. 607-632.
Petersson, Magnus, “Sweden and the Scandinavian Defence Dilemma,” Scandinavian Journal of History, Vol. 37, No. 2(May 2012), pp. 221-229.
Savolainen, Anna, “Mechanisms of threat: How Finland and Sweden abandoned non-alignment,” Comparative Strategy, Vol. 43, No. 2(March 2024), pp. 87-103.
Schweller, Randall L., “Unanswered Threats: A Neoclassical Realist Theory of Underbalancing,” International Security, Vol. 29, No. 2(Fall 2004), pp. 159-201.
Sinovets, Polina, and Renz, Bettina, “Russia’s 2014 Military Doctrine and beyond: threat perceptions, capabilities and ambitions,” NATO Defense College Research Paper, No. 117 (July 2015), pp. 1-12.
Smirnov, Pavel Ye., “The Accession of Finland and Sweden to NATO: Geopolitical implications for Russia's position in the Baltic Sea region,” Baltic Region, Vol. 15, No. 4 (2023), pp. 42-61.
Smura, Tomasz, “Russian Anti-Access Area Denial (A2AD) capabilities - implications for NATO,” Pulaski Policy Papers, No. 29 ( November 27, 2016), pp. 1-7.
Thies, Cameron G., “A Pragmatic Guide to Qualitative Historical Analysis in the Study of International Relations,” International Studies Perspectives, Vol. 3, No. 4 (November 2002), pp. 351-372.
Törnudd, Klaus, “Finnish Neutrality Policy During the Cold War,” The SAIS Review of International Affairs, Vol. 25, No. 2(Summer-Fall 2005), pp. 43-52.
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Waltz, Kenneth N., “Structural Realism after the Cold War,” International Security, Vol. 25, No. 1 (Summer 2000), pp. 5-41.
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Widian, Rizky,“Revisiting Balance of Threat Theory: The Case of Contemporary Southeast Asia in the Context of Great Power Contestation,”Jurnal Ilmiah Hubungan Internasional, Vol. 21, No. 1 (May 31, 2025), pp. 53-84.
Wieslander, Anna, “What makes an ally? Sweden and Finland as NATO’s closest partners,” Journal of Transatlantic Studies, Vol. 17 (March 2019), pp. 194-222.
Wieslander, Anna, “The Hultqvist doctrine – Swedish security and defence policy after the Russian annexation of Crimea,” Defence Studies, Vol. 2, No. 1 (August 16, 2021), pp. 35-59.
Winnerstig, Mike,“Security Policy at Road’s End? The Roles of Sweden and Finland in the Nordic-Baltic Defence Cooperation Process,”Lithuanian Annual Strategic Review, Vol. 12, No. 1 (November 2014), pp. 151-172.
（三） 書籍專章
Barrie, Douglas, “Russian Air-to-air Power: Re-make, Re-model,” in Michael Jonsson and Robert Dalsjö eds., Beyond Bursting Bubbles: Understanding the Full Spectrum of the Russian A2/AD Threat and Identifying Strategies for Counteraction(Stockholm: FOI, 2020).
Bronk, Justin, “Status and Future of Russian A2/AD Capabilities,” in Michael Jonsson and Robert Dalsjö eds., Beyond Bursting Bubbles: Understanding the Full Spectrum of the Russian A2/AD Threat and Identifying Strategies for Counteraction(Stockholm: FOI, 2020).
Forsberg, Tuomas, “Finland and NATO: Strategic Choices and Identity Conceptions,” in Cottey, Andrew, ed., The European Neutrals and NATO (New York: Palgrave Macmillan, 2017).
Hanhimäki, Jussi M., “Non-aligned to what? European neutrality and the Cold War,” in Bott, Sandra, Jussi M. Hanhimäki, Janick Marina Schaufelbuehl, and Marco Wyss, eds., Neutrality and Neutralism in the Global Cold War: Between or within the blocs?(London: Routledge, 2016).
Hedenskog, Jakob and Persson, Gudrun, “Russian security policy,” in Westerlund, Fredrik and Susanne Oxenstierna, eds., Russian Military Capability in a Ten-Year Perspective-2019 (Stockholm: FOI, 2019).
Jonsson, Michael, and Dalsjö, Robert, “Beyond Bursting Bubbles,” in Jonsson, Michael and Robert Dalsjö, eds., Beyond Bursting Bubbles: Understanding the Full Spectrum of the Russian A2/AD Threat and Identifying Strategies for Counteraction (Stockholm: FOI, 2020).
Lanoszka, Alexander, and Simón, Luis, “The Case for NATO Theatre-range Missiles in Europe,” in Jonsson, Michael and Robert Dalsjö, eds., Beyond Bursting Bubbles: Understanding the Full Spectrum of the Russian A2/AD Threat and Identifying Strategies for Counteraction (Stockholm: FOI, 2020).
Malmborg, Mikael af, “Sweden-NATO's Neutral 'Ally'? A Post-Revisionist Account,” in Schmidt, Gustav, ed., A History of NATO-The First Fifty Years, Volume 3 (London: Palgrave, 2001).
Malmlöf, Tomas, and Engvall, Johan, “Russian armament deliveries,” in Westerlund, Fredrik and Susanne Oxenstierna, eds., Russian Military Capability in a Ten-Year Perspective-2019 (Stockholm: FOI, 2019).
Meighan, Jamie, “Adaptive and Dispersed Basing within an A2/AD Environment: Opportunities, Threats, and Concepts,” in Jonsson, Michael and Robert Dalsjö, eds., Beyond Bursting Bubbles: Understanding the Full Spectrum of the Russian A2/AD Threat and Identifying Strategies for Counteraction (Stockholm: FOI, 2020).
Nielsen, Anders Puck, “Defeating the A2/AD Umbrella – Concepts for Exploitation of Russia’s Operational Weaknesses,” in Jonsson, Michael and Robert Dalsjö, eds., Beyond Bursting Bubbles: Understanding the Full Spectrum of the Russian A2/AD Threat and Identifying Strategies for Counteraction (Stockholm: FOI, 2020).
Pakkasvirta, Jussi, and Tuominen, Hanna, “From Cold War ‘Neutrality’ to the West: Finland’s Route to the European Union and NATO,” in Habtom, Naman Karl-Thomas, ed., Neutrality After 1989: New Paths in the Post-Cold War World (Bristol, England: E-International Relations, 2024).
Petersson, Magnus, “NATO and the EU ‘Neutrals’– Instrumental or Value-Oriented Utility?,” in Edström, Håkan, Janne Haaland Matlary, and Magnus Petersson, eds., NATO: The Power of Partnerships (London: Palgrave Macmillan, 2011).
Rumer, Eugene and Sokolsky, Richard, “Russian Threat Perceptions,” in Etched in Stone: Russian Strategic Culture and the Future of Transatlantic Security (Washington, D.C.: Carnegie Endowment for International Peace, 2020).
Roitto, Matti, and Holmila, Antero, “Liquid neutrality: paradoxes of democracy in Finnish and Swedish NATO discussions?,” in Koivunen, Anu, Jari Ojala, and Janne Holmén, eds., The Nordic Economic, Social and Political Model: Challenges in the 21st Century (Abingdon: Routledge, 2021).
Tangredi, Sam J., “Applying Historical Attributes of Anti-access Strategies to Current Analysis,” in Jonsson, Michael and Robert Dalsjö, eds., Beyond Bursting Bubbles: Understanding the Full Spectrum of the Russian A2/AD Threat and Identifying Strategies for Counteraction (Stockholm: FOI, 2020).
Wittmann, Klaus, “The Road to NATO's New Strategic Concept,” in Schmidt, Gustav, ed., A History of NATO-The First Fifty Years (London: Palgrave, 2001).
Wyss, Marco, Hanhimäki, Jussi M., Bott, Sandra, and Schaufelbuehl, Janick Marina “Introduction: a tightrope walk – neutrality and neutralism in the global Cold War,” in Bott, Sandra, Jussi M. Hanhimäki, Janick Marina Schaufelbuehl, and Marco Wyss, eds., Neutrality and Neutralism in the Global Cold War: Between or within the blocs? (London: Routledge, 2016).
（四） 學位論文
Chen, Lok Fung, “An Analysis of Finland's Decision to Enter into NATO after the Ukraine War,” Master’s thesis, Department of Political Science, National Taiwan University (2025).
Cole, Paul M., “Neutralite du jour: The Conduct of Swedish Security Policy Since 1945,” Ph.D. dissertation, Name of the department and university (1990).
Franzén, Johan, “A Qualitative Case Study of Finland's and Sweden's NATO Applications: Analysing the case through Liberalism and Neorealism,” Master’s thesis, Department of Government, Uppsala University (2023).
（五） 官方文件
“The Military Doctrine of the Russian Federation,” Embassy of the Russian Federation in the Kingdom of Thailand (December 25, 2014).
“Security in a new era: Report by the Inquiry on Sweden’s International Defence and Security Cooperation, Summary,” Government Offices of Sweden (September 9, 2016).
“Deterioration of the security environment-implications for Sweden, Ds 2022:8,” Government Offices of Sweden (May 13, 2022).
“The effects of Finland's possible NATO membership: An Assessment,” Ministry for Foreign Affairs of Finland (April 29, 2016).
“Foreign Policy Concept of the Russian Federation 2016,” Ministry of Foreign Affairs of the Russian Federation (November 30, 2016).
“The Concept of the Foreign Policy of the Russian Federation 2023,” Ministry of Foreign Affairs of the Russian Federation (March 31, 2023).
“Finnish Security and Defence Policy 2009,” Prime Minister’s Office (February 5, 2009).
“Finnish Security and Defence Policy 2012,” Prime Minister’s Office (March 15, 2013).
“Government Report on Finnish Foreign and Security Policy 2016,” Prime Minister’s Office (September 2016).
“Government Report on Finnish Foreign and Security Policy 2022,” Prime Minister’s Office (April 2022).
“Vårt framtida försvar,” Regeringen (September 23, 2004).
“Ett användbart försvar,” Regeringen (March 19, 2009).
“Regeringens proposition 2014/15:109 Försvarspolitisk inriktning-Sveriges försvar 2016–2020,” Regeringen (April 23, 2015).
“Regeringens proposition 2020/21:30 Totalförsvaret 2021–2025,” Regeringen (October 15, 2020).
“Government Report on Finnish Foreign and Security Policy,” Valtioneuvosto (October 29, 2020).
“Government report on changes in the security environment,” Government of Finland (April 13, 2022).
“Government’s Defence Report 2021,” Government of Finland (September 9, 2021).
“Neither Neutral Nor Non-aligned: The Europeanization of Finland’s foreign and security policy,” Finnish Institute of International Affairs (December 2013).
（六） 網路資源及其他
Dyomkin, Denis, and Forsell, Tuomas, “Putin hints Russia will react if Finland joins NATO,” Reuters (July 2, 2016).
Friis, Karsten, “Reviving Nordic Security and Defense Cooperation,” Carnegie Endowment for International Peace (October 2, 2024).
“Global Power Index with sub-components_1816-2050,” Frederick S. Pardee Center for International Futures (30 September 2025).
Johnson, Simon and Little, Tom, “Swedish, Polish forces simulate defence of Gotland amid Baltic tensions,” Reuters (September 25, 2025).
Metelinen, Sami, “Nato-jäsenyyden kannatus kasvoi vuodessa,” EVA (October 26, 2021).
Metelinen, Sami, “Suomalaiset liittyvät Natoon yhtenäisinä,” EVA (November 23, 2022).
“The Military Balance 2022,” International Institute for Strategic Studies (February 2022).
“The Military Balance 2023,” International Institute for Strategic Studies (February 2023).