In Massachusetts v. EPA, the Supreme Court for the first time clearly gave greater standing rights to states than ordinary citizens. The Court, however, failed to explain to what extent or when states are entitled to more lenient standing. This Article concludes that the Court has historically given states preferential status in federal courts when a state files a parens patriae suit based on the state\u27s quasi-sovereign interest in the health and welfare of its citizens or the natural resources of its inhabitants and territory. A quasi-sovereign interest is inherently less concrete and particularized than the types of injuries that individual citizens need for standing, yet the Court has allowed states standing to protect their general i...