2000 年總統大選結果所造成的中央政府首次政黨輪替，乃至 2004 年總統大選後，執政的民進黨因未能拿下國會過半席次，而擁有國會過半數席次的在野黨又無法組成政府，造成政府提出的諸多法案、政策、甚至人事案難以獲得國會在野（多數）黨的支持。本文以分立政府為理論基礎，並從議事阻撓觀點出發，嘗試比較一致政府時期與分立政府時期對於國會立法行為有無不同的差異影響存在，藉由研究分析結果，加以印證我國中央分立政府運作之影響，對照於美國學界的研究結果，似乎較傾向以 Sundquist 為首的學派所主張的論點。

Taiwan’s 2000 presidential election saw the first change in ruling parties. Although the Democratic Progressive Party (DPP) took the presidency once again in the 2004 presidential election, it nevertheless only gained a minority of seats in the Legislative Yuan. Owing to the fact that the opposition parties kept their hold on the legislative majority, the DPP failed in its attempts to reorganize the government, and nearly all of their numerous bills, policies, and personnel nominations were vetoed by the opposition parties. Through the application of the theory of divided government and focusing on the idea of obstructionism, this paper compares the periods of unified government and divided government regarding the actions of the Legislative Yuan and their various types of impact. Moreover, the research analysis contrasts with similar research from American academic circles, and in fact it finds that the legislative impact in our central divided government leans closer toward the main arguments given by the Sundquist school of thought.