The most important determinant of a case’s chances for Supreme Court review is a circuit split: If two courts of appeals have decided the same issue differently, review is substantially more likely. But practically every appeal in a patent case makes its way to a single court—the Court of Appeals for the Federal Circuit. How, then, does the Supreme Court decide whether to grant certiorari in a patent case? The petitions for certiorari in the Court’s patent docket suggest an answer: The Supreme Court looks for splits anyway. These splits, however, are of a different sort. Rather than consider whether two courts of appeals have decided the same issue differently, the Court looks to whether two fields of law conflict over the application of th...