在半總統制的研究當中，最常被探討的主題是制度與民主存續之 間的關係，但是對於修憲的政治學卻鮮少討論。本文探究半總統制如 何被操縱與修改以符合政治菁英本身的利益，也就是策略性的修憲。 半總統制的制度特性提供了策略性修憲的寬裕空間。就內容而言，策 略性修憲可分爲「加大總統權力型」與「加大國會權力型」。就動機而 言，可以分爲「獲取型」與「防制型」。本文假設當在位者預期本陣營 將可取得總統職位，或預期對手將獲得總理職位時，則可能發動修憲 來增強總統職位的權力；第二個是當在位者預期本陣營將可取得總理 職位，或預期對手將取得總統職位時，則可能發動修憲來增強國會權 力。透過對於土耳其、烏克蘭、喬治亞、中華民國和俄羅斯等五個半 總統制國家策略性修憲事例的探討，本文驗證了上述的假設，並根據 事例提出策略性修憲成敗的主要關鍵，是必須使得憲法權力流動的方 向（增強總統或增強國會）配合執政者對於選舉的預測。

Constitutional changes involving semi-presidentialism are more common than those having nothing to do with this hybrid system. The primary reason is that the institutional distance between parliamentarism and semi-presidentialism, and that between presidentialism and semi-presidentialism are shorter than the one between parliamentarism and presidentialism. This fact makes it easier for dominant political actors under semi-presidentialism to tinker with constitutional restructuring to enhance their political careers, or to sabotage those of their rivals. Empirical cases abound. Constitutional changes involving semi-presidentialism are of two types in terms of their direction: president-enhancing and parliamentenhancing. They can also be classified in terms of their motivation into two types: acquisitive and preventive, depending on whether the constitutional restructuring is for the benefits of the incumbents or for curbing the powers of their opponents. This article offers the assumptions that prominent incumbents are likely to launch acquisitive constitutional reform in the same direction as their expected career shifts, and that they tend to launch preventive constitutional reform to curb the powers of the constitutional positions that their rivals are likely to take. The cases of Turkey, Ukraine, Georgia, Taiwan, and Russia are explored and compared to test the assumptions. It is found that the success of strategic restructuring of the constitution hinges on the elite’s ability to shift constitutional power balance towards their electoral expectations and the accuracy of those expectations.