In the aftermath of the Supreme Court’s 2007 opinion in Bell Atlantic v. Twombly, judges and civil procedure scholars throughout the country divided on the opinion’s significance. In just twenty-four pages, Twombly uprooted the Conley v. Gibson standard for evaluating motions to dismiss a lawsuit under Rule 12(b)(6) of the Federal Rules of Civil Procedure. Under Conley, a court could dismiss a complaint only if it “appear[ed] beyond doubt that the plaintiff c[ould] prove no set of facts in support of his claim which would entitle him to relief.” That standard had governed motions to dismiss for fifty years, and embodied the liberal notice-pleading regime envisioned by the framers of the Federal Rules of Civil Procedure.3 But no more. Faced with a suit alleging that almost every major telephone company had engaged in anticompetitive conduct amounting to an antitrust conspiracy, the Court introduced a new system of “plausibility” pleading designed to curb discovery abuse and weed out frivolous lawsuits. Now, plaintiffs had to include in their complaints “enough factual matter” to “nudge[] their claims across the line from conceivable to plausible . . . .”

In responding to the opinion, some judges agreed with Justice Stevens’s view in dissent that Twombly “rewr[o]te the Nation’s civil procedure textbooks and call[ed] into doubt the pleading rules of most of its States,” whereas others viewed Twombly fundamentally as an antitrust case and assumed that the case’s effects would begin and end there. At the same time, scholars fractured over the opinion’s normative desirability; some viewed the opinion as a necessary bulwark against abusive practices by plaintiffs’ attorneys, whereas others saw it as going too far in assisting defendants. Almost immediately, Twombly became one of the most frequently cited cases in pleadings, even as judges split on how to apply its many strands.11 In the midst of all this confusion, perhaps only one thing was settled: Twombly’s reach was still unclear.