For example, new Justices Roberts and Alito voted for ever so slightly fewer conservative outcomes in those 33 cases than did Justice Scalia. Justices Roberts and Alito voted for 20 and 19 conservative outcomes, respectively, while Justices Scalia voted for 22 (Justice Thomas voted for 20 conservative outcomes). The cases in which Justices Roberts and Alito deviated from their conservative colleagues and voted for a liberal outcome were Day v. McDonough, in which Justices Roberts and Alito joined Justice Ginsburg’s majority opinion holding that district courts are permitted, but not obliged, to consider, sua sponte, the timeliness of a state prisoner's habeas petitions; Youngblood v. West Virginia, in which Justices Roberts and Alito joined a per curiam opinion holding, over the dissent of Justices Scalia, Thomas and Kennedy that a defendant had raised a constitutional claim sufficient to warrant remand to the state court; and Empire HealthChoice Assurance v. McVeigh, in which Justice Roberts joined Justice Ginsburg’s majority opinion finding no federal question jurisdiction in an insurance dispute, but Justice Alito voted in dissent in with Justice Breyer, Kennedy and Souter in favor of federal jurisdiction.
It is obviously impossible to argue that this scant record evidences much at all about the ideological direction of Justices Roberts' and Alito's jurisprudence, but it at least raises the possibility that those justices may share a jurisprudential philosophy that differs in some important ways from the Court's more established conservatives. Moreover, the scope of federal judicial power apparently embraced by both new justices in Day and Youngblood, and by Justice Alito in Empire Health Choice, is itself intriguing.
Also interesting is the alignment rates among the justices in those 33 cases. Using a methodology in which each justice can only be aligned with one opinion per case (so a justice who signs a concurrence is aligned only with justices signing onto that concurrence, not with all justices in the majority), Justices Roberts and Alito had the highest alignment rate, agreeing with each other in 82 percent of the cases. To put that in context, Justice Alito was aligned with Justice Thomas in only 73 percent of the cases and with Justice Scalia in only 64 percent. To the extent that this methodology tracks jurisprudential preferences more accurately than mere majority/dissent alignments, these numbers provide some (although again obviously very preliminary) evidence that Roberts and Alito may have more in common with each other than with the Court's more established conservative justices. For a more in-depth look at these numbers, see here.