在當代國際政治理論中，康德對國際政治的看法是經常被引用之權威，然而對此一文本本身的解讀仍有不少爭議，其中一個最主要爭議，就是要如何去理解康德所提出的國際問題的解答—即「自由國家聯盟」（Federation of Free States），這樣的一個解答讓許多康德的追隨者相當困惑，認為是康德之理論對現實的妥協，但筆者以為康德所提出的這個論點背後有更深意涵，並非出於經驗考量，本文藉由與盧梭所整理出版的法國聖皮耶教士原初永久和平計畫的文本之比較，為康德對國際關係問題所提出的解答提出一個可能的詮釋。

While Immanuel Kant’s influential essay on his plan for perpetual peace has been an important resource for contemporary studies on international relations, due to the obscurity of the text itself there still remain some unresolved interpretive difficulties. One main difficulty lies in understanding the solution that Kant proposed in his plan for perpetual peace, namely the federation of free states. Since what Kant proposed is a federation which member states are allowed to join or withdraw from freely, it leads to the criticism that lack of coercive force is very likely to lead to the collapse of the federation. Moreover, to contemporary cosmopolitans, Kant’s proposal also seems to fail to go beyond the limits of national states, and therefore can be considered outdated. The main aim of this essay is to re-interpret Kant’s proposal of free federation by comparing Kant’s theory of international relations with J.J. Rousseau’s revision of Abbé SaintPierre’s well-known project for perpetual peace. I argue that by putting Kant’s proposal into the context of Rousseau’s revision of Abbé Saint-Pierre’s project, it can be seen that rather than being outdated, Kant further develops and completes Rousseau’s unfinished revision by transforming Rousseau’s democratic republicanism into constitutional republicanism.