研討董仲舒理想政治主要有兩個方向，一自其天人思想，二自其君臣觀。若結合二者，以天人思想論其君權，歷來卻有伸君、抑君二種截然相對的結論。本文試深入其君臣論，聚焦在君臣極端緊張的「弒君」說，從董氏一、總論《春秋》弒君說，二、論責臣或責君之過？三、《春秋》書法與君臣倫理，四、弒君與其受命的主張等問題，說明董仲舒雖然主張回復三代君臣觀，仍以東周以來君王失德為鑑，從而退而求其次的提出「不成於賢」的誅心之法，從中肯定董氏仍以是否為人民所擁立的民本思想作為評價君王的根本要件。他並試圖轉化君權至上的漢初政局，不僅積極的以儒家道德式君臣論之應然，提出一政治理想，亦消極的對君綱之不振，主張弒君、革命之政權轉移為一歷史之應然與必然，透過《春秋》論述，致力於推動、轉換當代政治現實於其儒學理想治政中。

Discussions on Dong Zhongshu’s philosophy of ideal politics generally focus on two topics: (a) the interaction between heaven and mankind, and (b) the relationship between the monarch and the ministers. Two conflicting conclusions have been drawn from the latter: Dong argued either for absolute obedience of the ministers to the monarch, or for the subduing of the power of the Crown. This article will try to examine this topic of regicide from four perspectives: (1) an overview of Dong’s argument on regicide, (2) the accountabilities of the monarch and the ministers, (3) the writing principle of The Spring and Autumn Annals, along with the ethical relationship between the monarch and the ministers, and (4) the justification of regicide and the mandate. It will argue that although Dong advocated the ideal ethical relationship between the monarch and the ministers in the Xia, Shang and Zhou dynasties, he coined the term “unperfected Sage” in view of the immoral rulers of the state in the Eastern Zhou dynasty. Obviously, Dong’s evaluation of the success of the sovereignty was people-oriented. Based on Confucian virtue theory, Dong then proposed his ideal politics, illustrating the accountabilities of the monarch and the minsters on one hand while passively justifying the necessity of the revolution, or the regicide of an immoral monarch on the other. Through his elaborations on The Spring and Autumn Annals, Dong strived for the alignment of the reality of contemporary politics with his Confucian ideal politics.