Swing Votes on the Current Supreme Court: The Joint Opinion in Casey and Its Progeny

Abstract

In 1992, United States Supreme Court Justices Sandra Day O'Connor, Anthony Kennedy, and David Souter published their famous "joint opinion" in Planned Parenthood v. Casey. That opinion presented a relatively detailed theory on how to give content to general constitutional provisions, like the meaning of liberty under substantive due process analysis, and the relative weight to be given to precedent in deciding constitutional cases. Given their "joint" signing of this opinion, many commentators predicted that these three Justices would form a relatively reliable "block" which would control the outcome of Supreme Court cases for the foreseeable future.

It has certainly turned out that Justices O'Connor, Kennedy, and Souter are the swing votes on the Court today. In most close cases, there is a conservative block of Chief Justice Rehnquist and Justices Scalia and Thomas on one side, and a more liberal block of Justices Stevens, Ginsburg, and Breyer on the other side. However, it has not turned out that Justices O'Connor, Kennedy, and Souter always vote together. Indeed, in close cases they will often split 2-1, sometimes with two joining the conservative block, and other times two joining the more liberal block. This split occurs because although these three share the decision-making philosophy represented in Casey, nuances in how the theory is understood and applied in different circumstances have led to different results.

Exploring these different nuances is the subject of this article. For purposes of this exploration, every 5-4 opinion of the Supreme Court over the last four Terms (1997-2000) will be considered, as well as other notable 5-4 opinions of the Court since Casey was decided in 1992. A complete tabulation of the voting patterns in these cases appears in Appendix A of this article.