論美國法上公民適格性及國籍授與法理──兼評川普移民政策

Worthiness for Citizenship and Principles of Citizenship under U.S. Law: Commentaries on Trump's Immigration Policies

全球不平等下，國界與國籍之差異即為個人生存條件與發展機會之差異。在國界嚴密管制下，各國國籍授與條件之設定，攸關兩項疑問：一、國家對先來者與後到者之要求有何不同？為何不同？二、被接受成為公民者與被拒絕者有何不同？為何不同？本文先就當代憲政國家對國籍授與之基礎原則及其發展，包括傳統的出生地原則（jus soli）、血緣原則（jus sanguinis），以及嗣後的同意原則（consensual citizenship），一直到晚近學者所提出之連結性原則（jus nexi）與時間原則（jus temporis），逐一探討其背景及理據，以及評估各該原則之效益，亦即：個別原則是否真有助國家篩選出更好的公民並回應上述兩項疑問？其後本文再基於國籍授與之基礎原則及法理，針對美國川普總統於2017年上任後所主導之兩項重大移民政策──廢除DACA方案與廢除與生俱來公民身分──進行介紹與評點，以作為同屬當代移民社會之臺灣在國籍授與及移民政策設計上之借鏡。

In a world of global inequality, state borders and different nationalities denote people's different living conditions and opportunities. With the guarded borders, two inquires underlie the principles of citizenship, namely, the principles relied on by a state to grant citizenship to individuals. First inquiry pertains to whether or not there is a difference between the requirements for early settlers and for newcomers and why there is a difference? The second inquiry involves whether or not there is a difference between the individuals who are granted citizenship and those who are rejected and why there is such a difference? This Article first reviews the principles of citizenship including the traditional jus soli and jus sanguinis, the recent proposition of consensual citizenship, and the latest theories of jus nexi and jus temporis by looking into the context and rationale of each proposed principle and evaluates the effectiveness of each. Specifically, this article examines whether a principle helps the nation select the better citizens and responds to the two aforementioned inquiries. Secondly, based upon the fundamental principles and legal theories of citizenship, this article introduces and comments on two major immigration changes led or proposed by President Trump since his 2017 inauguration - rescinding DACA and ending birthright citizenship. This article aims at bringing some insight into the construction of citizenship and immigration policies for countries of immigration like Taiwan.