美國憲法第三條規定司法權力僅限於「案件」和「爭議」，但該條並未清楚闡明何謂「案件」及「爭議」。美國最高法院透過詮釋指標性案件指出，當事人適格原則是構成案件或爭議的核心要件，它包含三個要素：事實上損害、因果關係及可救濟性。然而當事人適格原則已被認為是當代法律中最令人困惑及充滿問題的概念。本文之目的即在以突破性的方式，探尋當事人適格原則的內含要素，並嘗試提出：在特定的角度下，若當事人適格此一原則並不是一種實體上的法律權利，也不是一種程序上的法律權利，透過正義的觀點來探討當事人適格原則更為妥當，而羅爾斯正義論可以是檢視當前美國法院詮釋當事人適格原則的有利工具。

Article III of the U.S. Constitution limits judicial power to ＂cases＂ and ＂controversies,＂ but it does not clearly say what ＂case＂ means and what ＂controversy＂ is. The Supreme Court has interpreted via landmark cases that standing doctrine is the core element of the case-or-controversy requirement and has three elements: injury-in-fact, causation, and redressability. However, standing has proven to be a confusing and problematic concept in modern law. The purpose of this article is to find a groundbreaking way to define the criteria of standing. This article tries to argue that if, viewed from the specific angle, standing is not encompassed by substantive rights or procedural rights, it is better to devise its doctrine through the lens of justice. And, Rawls' justice theory could be a good tool for examining the current standing doctrine laid out by the court.