In a recent article in the New York Times Adam Liptak describes the increasingly partisan splits on the Supreme Court. More than at any time in its history, he argues, the divisions in cases follow partisan as well as ideological alignments. Thus, today the five justices appointed by Republican Presidents (the Chief Justice, Scalia, Kennedy, Thomas and Alito) vote consistently more conservatively than those appointed by Democratic Presidents (Ginsburg, Breyer, Sotomayor, Kagan).
For the moment I will accept Liptak’s statistics and focus on his explanations. Liptak argues that partisan polarization is the result of increased polarization more generally, as Republicans and Democrats move to become cohesive ideological parties, distant in their policy preferences. Moreover, Liptak argues Presidents have become better at predicting justices’ votes. These factors are certainly relevant, but I think they miss one important change. Originalism and its often close cousin in statutory interpretation—textualism— today create a larger gulf in jurisprudential approaches to the Constitution and statutes between Republican and Democratic appointees.
There was not such a consistent jurisprudential chasm in the Court for much of the latter part of the twentieth century. There were no originalists on the Court when Scalia joined it. Thomas then became another powerful originalist voice. While Alito and Roberts are not pure originalists, the original meaning of the text has a strong pull for them even if precedents restrain the extent of its power. Their opinions on the commerce clause in Sibelius are excellent examples of the power of the text; the Democratic appointees did not even substantially respond to the originalist arguments.
Before the rise of the originalism, Republicans did not have the jurisprudential resources to resist the constant progressive drive in our legal culture. That drive is an overriding reason that Republicans and Democrats appointees were more ideologically homogeneous in the latter part of the twentieth century. The progressive tendency in law today continues to be pervasive. The bar stands to the left of the American public because of its pecuniary interests in legal change and the academy stands to the left of the bar because intellectuals today are by and large on the left. (We can leave the reasons for the latter phenomenon for another day).
Because of this leftward current, justices who were Republican appointees previously tended to drift or indeed veer to the left once on the Court, as the ideological scores on which Liptak himself relies shows. This drift was not the result of the partisan position of the President but of the legal culture. Moreover, while it is true that Republican Presidents became better in general at choosing justices who will be conservatives, their new found skill is due in large part to the rise of originalism. If the difference between conservatives and progressives is largely a matter of prudence as it was in the day when the second Justice Harlan was the leading conservative (link no longer available), it is very difficult to decide who will maintain a conservative jurisprudence.
Some may think that this explanation is of no real weight because originalism is just a cover for Republican policy preferences. I think this claim false. Originalism revived as an intellectual, not a partisan project. While originalism in general leads to more conservative results than living constitutionalism does today, that is not analytically true. And the most originalist justices on the Court not infrequently follow the philosophy to reach liberal results, as in matters like flag burning, the Confrontation Clause and the role of juries. Finally, the reasons that conservatives are attracted to originalism go beyond results, but are rooted in fears about the discretionary power of elites and respect for the achievements of the past—matters that transcend partisan policy differences.