SCOTUS Preferences in Civil Rights Cases

Even with the Supreme Court in summer recess the Justices have ruled on a slew of challenges to states’ laws affecting voting rights (for example) and regulations (for example).  These decisions often have ideological dimensions as is apparent from the alignment of dissenting coalitions.

With eight rather than the typical nine Justices currently sitting on the Supreme Court, there is smaller likelihood of achieving the requisite majority to impede current state legislation and so state laws are more likely to be upheld than would be the case under a nine-member Court.

Professor Rick Hasen, a noted expert in election law, wrote a year ago (prior to Justice Scalia’s death) about the central relationship the Supreme Court and civil rights.  Now with a Court that is less likely to act due to the number of Justices and with an impending presidential election, the resonance of this claim is further underscored.

There are several ways to infer the Justices likely positions on issues such as voting rights given information we already know about them.  One such way is using the Justices past votes.  Some of the most widely used predictive metrics of the Justices’ votes are based on past votes (for more on ideal points here is a link to Profs. Andrew Martin and Kevin Quinn’s Martin and Quinn Scores).   While these numeric measures are very accurate in giving a sense of Justices’ likely voting patterns, they also assume voting equivalence across a wide range of issues (which is not wrong as is apparent from the predictive accuracy of these numbers, but does generalize quite a bit of theoretical terrain).

Another way to understand the patterns of Supreme Court Justices’ votes is through a series of concentric circles.  The circle with the greatest diameter encompasses all cases before the Justices.  A smaller circle encompasses cases dealing with individual rights or civil liberties, and an even smaller one encompasses civil rights.  We can drill down to a single point on this map based on an individual case.  Using Martin and Quinn’s method for ideal point generation, I generated two sets of such points for the Roberts Court Justices – one for the larger circle of individual rights and one for the smaller circle of civil rights.  When using these probabilistic methods for understanding the Justices’ voting preferences (I based these on 130,000 simulations for the each of the figures in this post), there is a tradeoff between using a fewer number of more specifically tied cases and using a larger number of cases that relate more generally.  For this reason, I look both at civil rights more specifically and individual rights more generally, yet I do not focus solely on voting rights cases because of the insufficient number of these standing by themselves.

The civil rights numbers are intended to convey an approximation of the Justices’ preferences in the area of voting rights (this also encompasses other civil rights issues such as gender or race-based discrimination, immigration-related cases, etc.).  With that, the figure below depicts the Justices’ preferences in civil rights cases since the beginning of the 2005 Supreme Court Term (when Justice Roberts took the position of Chief Justice. Justice O’Connor was removed from analyses due to the minimal number of cases she voted on in the 2005 Term).

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The raw preference numbers are unimportant in the figure.  The focus is the Justices’ relative positions and how their positions shift over time.  There are several interesting points to note from this vantage.  First, Justice Thomas is isolated in the far conservative zone.  Justice Kennedy shifted the most over the years moving from moderately conservative on such issues to moderately liberal (his preference line is highlighted in the chart).  The other Justices fall into somewhat predictable patterns with Justice Alito a little to the right of Justice Roberts and Justices Breyer, Sotomayor, Kagan, and Ginsburg all to the left of the middle.  This suggests a trend towards more liberal rulings on civil rights issues over time and with the movement of Justice Kennedy, the possibility of a five-member liberal majority in such cases even on an eight-member Court.

When looking at the Justices’ preferences on individual rights issues more generally (these include issues ranging from abortion rights to those protecting the criminally accused as well as civil rights) we get a better picture of the Justices’ preferences in civil rights cases as well. The figure below shows the Justices’ average preferences in individual rights cases for the 2005-2015 Terms (or until they left the Court) with the blue bars and a black line for each Justice noting their average for civil rights cases across the same set of Terms.


First, the convergence of the two sets of averages helps to clarify their accuracy in positioning the Justices.  The Justices all move in the same ideological directions in civil rights and civil liberties (or individual rights) cases, and only to a different degree.  This degree is somewhat telling though.  While Justice Thomas edges to the right in civil liberties relative to his position in civil rights, all of the rest of the Justices are farther to the left in civil rights of their positions in civil liberties more generally.  It is worth highlighting that these metrics are averages and do not provide a Term-by-Term breakdown, however, they do compare the Justices positions in the larger and smaller concentric circles described above.

Taken together these figures show the Court as a whole favoring the liberal position in civil rights cases, especially over time and up to the current Term.  It presents the possibility of a majority coalition in these cases even on an eight-member Court.  It also shows that the Justices preferences in civil rights cases tend to be more liberal than in individual rights cases more generally.  Finally, it shows that Justice Thomas is an outlier among the Justices in both of these areas, even when compared to the other more conservative Justices on the Roberts Court.


On Twitter @AdamSFeldman

The Justices votes in these cases were derived from the United States Supreme Court Database.  I used Martin and Quinn’s one dimensional dynamic ideal point algorithm from MCMCPack in R to calculate the Justices’ preferences.

Figures Updated 9-19

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