This week we take a look at one of the two primary jurisdictional means by which a case may be brought in federal court – id est federal diversity jurisdiction. In addition, we examine what has been referred to as the “Gaping Hole Problem” in diversity jurisdiction that arises from the potential exercise of supplemental jurisdiction. We also examine the approach the D.C. Circuit took in In re Lorazepam & Clorazepate Antitrust Litigation in handling a case in which the presence of nondiverse parties threatened to defeat federal diversity jurisdiction.