半總統制是新興民主國家廣為採用的政府制度類型，而現有關於半總統制的研究不論是著重憲法規範或實證行為面向，對於總統常態性的政策權限設計和相關的決策機關配置的系統性探討較為欠缺。本文試圖藉由包括臺灣在內共 21 個半總統制民主國家憲法設計的探索，讓半總統制的研究和理論能觸及總統常態性的治理課題，是半總統制研究中的新嘗試。本文焦點在於系統性解析多個國家憲法中總統的政策權與決策機關之設計模式，並進一步探討其與半總統制憲法上的次類型和實際的運作類型之關係。藉由多國案例的分析，本文呈現了重要而豐富的研究發現。研究核心發現在於，當總統具有特定政策權限時，憲法也大都配置政策諮詢或決策機制，而總統是否具主持內閣會議(或部長會議)權限，並與半總統制之憲法類型和實務類型都有一定的關聯性，因此，從「誰主持內閣會議」這個問題切入，可以相當程度辨識出該國憲法設計之原意，是讓其半總統制的行政權中樞傾向在總統或總理身上。最後，本文也對臺灣的相關憲法設計，提出了延伸的討論和思考。

Semi-presidentialism has been a popular form of government in emerging democracies. However, systematic analyses on the presidents’ powers in policy-making or on the related mechanisms of their decision- making process have been scarce. To fill in the gap in the field, this article surveys the experiences of 21 democratic countries. With a focus on constitutional design of president’s powers in policy and decision-making mechanisms, this article also tries to discover their relationship with sub- types of semi-presidentialism. The results showed that the president’s power is crucial to political accountability of the government. When a country’s constitution does not explicitly give powers of policy making to its president, its constitutional system seems to fall into a type of premier-presidential. Finally, this article reflects some opportunities and challenges for constitutional design in Taiwan.