In Exxon Mobil Corp. v. Allapattah Services, Inc., 545 U.S. 546 (2005), the Supreme Court took its first stab at construing the supplemental jurisdiction statute, 28 U.S.C. § 1367 - a statute that has provoked a great outpouring of scholarly criticism and debate since its enactment in 1990, and generated several conflicts among the lower federal courts. This Article focuses on important features of the Court's reasoning in Exxon Mobil v. Allapattah, including the Court's conflation of a with a claim. Part I discusses the reasoning in Allapattah and Rosario Ortega in detail, showing among other things when and why the Court conflated a with a claim. As part of that discussion, Part I addresses the Court's treatment of indivisibility theory and contamination theory and how that treatment influenced the Court's view of civil actions. It also considers the relevance of the Supreme Court's decision in City of Chicago v. International College of Surgeons, 522 U.S.156 (1997), to its reasoning and conclusions in Allapattah. Finally, Part I compares the reasoning and ultimate holdings of Allapattah and Rosario Ortega - and the views of the dissent - with the recommendations in the American Law Institutes Federal Judicial Code Revision Project, published in 2004, and with my own thoughts on the issues raised. While my views are more similar to those of the dissent than to those of the majority, I believe that the outcome in Allapattah (but not in del Rosario) is correct because of the presence of a civil action within the original jurisdiction of the federal courts before any class is certified. Part II provides many illustrations of how, if the lower federal courts were to accept the Court's redefinition of and claim, and carry it into other contexts in which the terms have long been understood to share the meanings of those words and phrases as they are used in the federal question and diversity subject-matter jurisdiction statutes, significant and undesirable changes in doctrine would result - particularly in cases removed from state court. Part III then ponders why the federal courts nonetheless have forgone the opportunity to extend the redefinition or conflation into such other statutory contexts, despite some reasons to do so. It considers the jurisprudential question of the propriety of eschewing the precedent set by Allapattah and Rosario Ortega in their treatment of claim and action, and argues that the courts are wise to ignore - but would do better to distinguish and limit - the reasoning of Allapattah and Rosario Ortega and to decline to extend it into the interpretation of other jurisdictional statutes. Finally, Part III urges better drafting by Congress, to avoid strained interpretations invited by poor legislative drafting.