俄烏戰爭後芬蘭選擇加入北約的決策分析

Abstract

本碩士論文探討芬蘭在2022年俄烏戰爭爆發後，如何放棄其長期奉行的軍事不結盟政策並加入北大西洋公約組織（NATO）的決策過程。透過基於格雷厄姆·艾利森（Graham Allison）理性行為者模式（Rational Actor Model）的全面成本效益分析，本論文研究俄烏衝突如何根本性地改變了芬蘭的戰略考量，導致其在戰爭開始後三個月內迅速加入北約。 論文採用雙重理論框架，結合理性行為者模式與史蒂芬·沃爾特（Stephen Walt）的威脅平衡理論（Balance of Threat Theory），解釋芬蘭前所未有的外交政策轉變。理性行為者模式為理解芬蘭作為追求國家利益最大化的統一決策主體提供分析基礎，而威脅平衡理論則闡明芬蘭對俄羅斯侵略意圖（aggressive intentions）的認知，而非僅僅軍事能力，如何驅動其聯盟決策。 分析框架將自變量分為成本相關因素和效益相關因素。成本相關變量主要涉及芬蘭正式加入北約前俄羅斯軍事報復的可能性。分析顯示，俄羅斯在烏克蘭的軍事退化——體現在未能實現戰爭目標、從北方地區大規模調兵、人員裝備重大損失、部隊士氣低落，以及廣泛的動員困難——顯著降低了俄羅斯對芬蘭潛在報復的可能性和嚴重性，從而降低了北約成員資格的相對成本。 效益相關變量聚焦於北約第5條集體防禦保障的價值，這與芬蘭對未來俄羅斯威脅的評估直接相關。論文展示俄烏戰爭如何促使芬蘭決策者透過三個關鍵視角重新評估俄羅斯的侵略意圖：將衝突與芬蘭冬季戰爭經驗聯繫的歷史記憶、俄羅斯對北歐地區日益增強的關注，以及在普京日益不可預測領導下俄羅斯帝國主義和擴張主義的感知升級。 此論文採用質性文獻分析方法，檢視芬蘭政府報告、議會辯論、官方聲明和國防評估。比較芬蘭2021年和2024年國防報告顯示了從強調自主防衛能力的軍事不結盟政策向優先考慮集體安全保障的全面北約整合的轉變。 此論文表明，芬蘭的北約加入決定基於成本下降和效益增加，代表了理性的戰略選擇。本論文透過提升對不對稱權力條件下小國安全決策的理解，論述歷史經驗如何增強而非扭曲理性威脅評估。論文更揭示威脅認知，特別是對侵略意圖的認知，在聯盟形成中比總體實力計算更具決定性，嘗試為小國在大國競爭時代應對複雜地緣政治變革提供了其見解。

This thesis examines Finland's decision to abandon its longstanding policy of military non-alignment and join NATO following the 2022 Russia-Ukraine War. Through a comprehensive cost-benefit analysis grounded in Graham Allison's Rational Actor Model, this study investigates how the conflict fundamentally altered Finland's strategic calculus, leading to its rapid NATO accession within three months of the war's commencement. The thesis employs a dual theoretical framework combining the Rational Actor Model with Stephen Walt's Balance of Threat Theory to explain Finland's unprecedented foreign policy transformation. Whilst the Rational Actor Model provides the analytical foundation for understanding Finland as a unitary decision-maker seeking to maximise national interests, the Balance of Threat Theory illuminates how Finland's perception of Russian aggressive intentions, rather than mere military capabilities, drove its alliance decision. The analytical framework divides independent variables into cost-related factors and benefit-related factors. Cost-related variables primarily concern the likelihood of Russian military retaliation before Finland's formal NATO accession. The analysis reveals that Russia's military degradation in Ukraine—evidenced by unfulfilled war objectives, massive force reallocations from northern regions, substantial personnel and equipment losses, declining troop morale, and widespread mobilisation difficulties—significantly reduced the probability and severity of potential Russian reprisals against Finland, thereby lowering the relative costs of NATO membership. Benefit-related variables focus on the value of NATO's collective defence guarantees under Article 5, which correlates directly with Finland's assessment of future Russian threats. The thesis demonstrates how the Russia-Ukraine War prompted Finnish decision-makers to reassess Russian aggressive intentions through three critical lenses: historical memory connecting the conflict to Finland's Winter War experience, Russia's intensified focus on Northern European regions, and the perceived escalation of Russian imperialism and expansionism under Putin's increasingly unpredictable leadership. The research employs qualitative document analysis of Finnish government reports, parliamentary debates, official statements, and defence assessments. Comparison of Finland's 2021 and 2024 Defence Reports illustrates the transformation from military non-alignment emphasising autonomous defence capabilities to full NATO integration prioritising collective security guarantees. Key findings demonstrate that Finland's NATO accession represented a rational strategic choice based on decreasing costs and increasing benefits. The thesis advances understanding of small state security decision-making under asymmetric power conditions and demonstrates how historical experience enhances rather than distorts rational threat assessment. It reveals that threat perception, particularly regarding aggressive intentions, proves more decisive in alliance formation than aggregate power calculations, offering insights for small states navigating complex geopolitical transformations in an era of great power competition.