立法院提案網絡之政黨合作結盟初探：重大社會事件是否加劇政黨極化？

A Study of Political Party Cooperation in the Legislative Yuan Proposal Network: Have Major Social Events Intensified the Polarization of Political Parties?

楊舒喻(Shu-Yu Yang)

指導教授 ： 黃心怡

國立臺灣大學/社會科學院/公共事務研究所/碩士(2020年)

https://doi.org/10.6342/NTU202003893

摘要

回顧臺灣民主政治發展的脈絡，自1990年代落實民主選舉制度，2000年後政黨逐漸區分成泛藍與泛綠兩大陣營，社會上也普遍認為藍綠對立與分化現象日益嚴重。相較於多數文獻採用記名表決資料進行國會互動分析，本研究採用立委提案連署資料作為研究主體，探討政黨內、外的結盟行為；另一方面，由於提案連署行為乃為立法過程的前期，立委普遍擁有更大的自由表現空間，本研究透過社會網絡分析的方法，提取提案連署過程中立委之間展現的關係，並透過關注極化意涵中陣營內的凝聚力與陣營間的排拒力，發掘隱含其中的結構層面的互動。
本研究分析第八屆立法院提案資料（提案數 = 4,576）、及所有曾經參與提案連署的立委（立委數 = 123），根據此屆所發生之重大社會事件：馬王政爭與太陽花運動，比較事件發生前後對於政黨合作互動的動態變化，也比較不同類型法案的差異。利用隨機度序列模型（Stochastic Degree Sequence Model，SDSM）方法，將「提案-立委」之二維資料轉換為「立委-立委」政治關係的「正向關係」（+1）、「無顯著關係」（0）或「負向關係」（-1）的符號網絡（signed network），將政黨之間的關係分為內部凝聚力強、外部關係差之「強極化」以及內部凝聚力強但外部關係不顯著之「弱極化」來捕捉極化的現象。
本文發現：（1）第八屆立法院已呈現強極化，跨政黨合作多侷限於同陣營之間，意謂著政黨的統獨立場標籤在解釋立委的互動關係上具有好的解釋力。（2）在強極化的結構下，三種類別的議案中，兩陣營在外交國防結合政治類議案的極化程度最高，財經類與社會福利類的結果較為接近，但財經類議案潛在最具合作空間。（3）在馬王政爭前，呈現陣營內凝聚力強、陣營亦顯著對立之「強極化」現象；馬王政爭後，陣營內凝聚力下降，而跨陣營間的合作增加，使得政黨極化程度下降，不過很多立委之間的關係轉為無顯著關係，而泛綠陣營的改變較明顯；太陽花運動後，兩陣營各自歸隊，陣營內凝聚力增強、且陣營之間排拒力也加大，形成強極化現象。另一方面，立委間、政黨間的互動除了立場是否一致外，如果沒有政治互信的累積，也未必有意願、或者並沒有開展交流。

關鍵字

立法院 ； 政黨凝聚力 ； 政黨對立 ； 政黨極化 ； 連署 ； 社會網絡分析 ； 隨機度序列模型

並列摘要

Looking back at the development of Taiwan’s democratic politics, since the implementation of the democratic electoral system in the 1990s, political parties have gradually divided into two camps, pan-blue and pan-green after the year 2000, and society generally believes that the oppositions and divisions between pan-blue and pan-green are becoming increasingly serious. Compared with most studies that use roll-call voting records for parliamentary interaction analysis, this study uses the data of legislators' sponsorship- cosponsorship as the main body of the research to explore alliances within and outside the party. On the other hand, because the act of sponsorship- cosponsorship is the early stage of the legislative process, legislators generally have more freedom to express themselves, and therefore, this study uses social network analysis to extract the relationship between legislators in the process of sponsorship- cosponsorship, and pays attention to the cohesion within the camp and the derogation between the camps in the meaning of polarization, in order to explore the implicit structural level of interaction.
This research analyzes the proposal data of the 8th Legislative Yuan (number of proposals = 4,576), and all legislators who have participated in the sponsorship- cosponsorship (number of legislators = 123). According to the major social events that occurred in this session, which is the Ma-Wang political struggle and the Sunflower Movement, the study compares the dynamic changes of party cooperation and interaction before and after the incidents, and compares the differences of different types of bills. Using the Stochastic Degree Sequence Model (SDSM) method, the two-dimensional data of "proposal*legislators" is converted into the political relationship of "legislators*legislators", with 3 possible relationships: "positive (1)", "no (0)" or "negative (-1) ". This study also divides the relationship between parties into "strong polarization", the case of in-group favoritism with out-group derogation , and "weak polarization", the case of in-group favoritism without out-group derogation.
The research findings show: (1) The Eighth Legislative Yuan has shown strong polarization, and cross-party cooperation is mostly confined to the same camp, which means that the party’s unification-independence preference has a good explanatory power in explaining the interaction between legislators. (2) Under a strongly polarized structure, among the three types of bills, the two camps have the highest degree of polarization in the combination of diplomacy and defense and political bills. The financial and social welfare bills are closer, but the financial bills have the most potential to cooperation. (3) Before the Ma-Wang political struggle, there was a phenomenon of "strong polarization" with strong cohesion within the camp and derogation between the camps; after the Ma-Wang political struggle, the cohesion within the camp declined, and the cooperation between the camps increased, which made the degree of polarization decrease; however, the relationships between many legislators turned into no significant relationships, and the changes in the pan-green camp were more obvious; after the Sunflower Movement, the two camps returned to their respective teams, the cohesion within the camps increased, and the derogation between the camps increased, forming a strong polarization phenomenon. On the other hand, in addition to whether the positions of legislators and political parties are consistent, if there is no accumulation of political mutual trust, legislators may not have the motivation to cooperate.

並列關鍵字

Taiwan Congress ； intra-party cohesion ； inter-party conflict ； party polarization ； co-sponsorship ； Social Network Analysis ； Stochastic Degree Sequence Model (SDSM)

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