Since Chief Justice John Roberts joined the Supreme Court in 2005, several pairs of justices have had notable disagreements in multiple cases.  This is at least in part due to the justices’ polarity of viewpoints and interpretive methods.  It nonetheless creates clear divisions on the Court as the justices have hardened viewpoints on many substantive issues (Jeffrey Segal and Harold Spaeth wrote a great paper comparing justices’ stability of voting in substantive areas versus their choices in following the evolutionary trajectory of Supreme Court precedent).

Sure, plenty of justices have disagreed with one another over the past eleven terms, but who has disagreed the most.  In this post I’m not interested in disagreements in terms of voting in different directions. I’m interested in justices that took the time to write opinions in opposite directions in the same cases – that is justice pairs where one justice was the majority author and another authored a dissent in multiple cases (these pairs are where the majority author is the same and so is the dissent author and so I only look at these pairs in one direction).  Without further ado below are the most antagonistic pairs of justices based on majority and dissent authorship.

This figure takes account of all majority/dissent author pairs with at least nine occurrence of the same majority and dissenting authors.  There are more than a few such pairs as the total number is 21.

The following figure shows the justices frequencies as majority and dissenting author in these 21 groups.

Although Justices Thomas and Breyer were in dissent most often and Justice Kennedy was the most frequent majority author, there is striking parity among the justices in both categories.  Aside from Justice Kennedy’s dominance as majority author in these instances, the rest of the justices in the majority figure are split almost evenly.

What drives these pairs?  At first look it doesn’t appear that ideology in isolation is the main factor.  Martin and Quinn Scores presented in the graph below show the justices’ ideologies from most conservative (the higher lines) to most liberal (the lower lines).

If ideology was the main factor at play then we might expect a Thomas/Ginsburg, Thomas /Sotomayor, Scalia/Sotomayor, or Scalia/Ginsburg pair atop the field.  None of these pairs are towards the top of the initial graph though, while five pairs including Justice Kennedy as majority author are in the top ten for most dissents.  Justice Kennedy has been the Court’s ideological median vote, however, for many years now.  In terms of dissents, one might expect Justice Thomas to be the leader given his recent history of high dissent counts. Justice Breyer, however, is the dissenting justice in more top ten pairs with three compared to Justice Thomas with two.

No, the justices’ ideological differences do not seem to be the main feature driving these regular entanglements.  With Justice Kennedy as the majority author in half of the top ten pairs, there appears to be a regular occurring factor in Justice Kennedy’s opinions that catalyzes such dissension.  Some of this might have to do with the divisiveness of the opinions that Justice Kennedy tends to author.  When I looked at the justices since 1946 that authored the most 5-4 split vote decisions, Justice Kennedy was the only sitting justice on the list.

While ideology does not tell the entire story, perhaps it still does play a meaningful role.  When looking at the decision direction of the majority (as coded in the Supreme Court Database) for all cases in the top three pairs (Kennedy/Scalia, Kennedy/Thomas, and Scalia/Breyer) ideology seems to be a motivating factor in the justices’ choices.

Justices Scalia and Thomas are/were known to vote on the conservative end of the Court’s spectrum.  The decisions where they dissented from Justice Kennedy’s opinions are predominately when Justice Kennedy authored liberal decisions.  Similarly, Justice Scalia predominately dissented from Justice Breyer, one of the Court’s more liberal justices, when Justice Breyer penned liberal decisions.

To probe a bit deeper into what is driving the top three majority/dissent pairs, the case issue areas is shown in the following chart.

This figure provides more clarity to the sources of the justices’ disagreements.  Justice Scalia, for example, primarily dissented when Justice Kennedy wrote liberal majority opinions in the areas of criminal procedure (mainly rights-based) and civil rights.  Looking at the instances of Justice Scalia dissenting from Justice Kennedy’s majority opinions over time since 2005, we see that Justice Scalia averaged around two dissents a term with some fluctuations above and below this average.

An example of this combination of justices in the criminal procedure area is the case Maryland v. King.  In this case, Justice Kennedy wrote the Court’s majority opinion holding that states could collected DNA from people that are arrested for serious crimes prior to conviction.  Justice Scalia has many strong worded lines in the dissent including,

“The Court’s assertion that DNA is being taken, not to solve crimes, but to identify those in the State’s custody, taxes the credulity of the credulous”

and

“Make no mistake about it: As an entirely predictable consequence of today’s decision, your DNA can be taken and entered into a national DNA database if you are ever arrested, rightly or wrongly, and for whatever reason.”

Justice Thomas has mainly dissented from Justice Kennedy’s opinions in the areas of criminal procedure, due process, and civil rights.  These dissents are featured in the cases invalidating DOMA and legalizing same-sex marriage –  United States v. Windsor and Obergefell v. Hodges – among other cases.

Justice Thomas’ dissents from Justice Kennedy’s majority opinions hit their peak during the 2015 term.  During this term Justice Thomas dissented when Justice Kennedy authored the majority opinions in Fisher v. University of Texas, Encino Motorcars v. Navarro, Montgomery v. Louisiana, Williams v. Pennsylvania, Welch v. United States, and Tyson Foods v. Bouaphakeo.

Lastly, Justice Breyer’s dissents from Justice Scalia’s opinions mainly fit into the criminal procedure and judicial power areas.

Justice Breyer had the most dissents in a term from Justice Scalia’s majority opinions in 2008.  In that term Justice Breyer dissented in Energy Corp. V. Riverkeeper, Summers v. Earth Island Institute, FCC v. Fox Television, and Montejo v. Louisiana.  One of the strongest sources of disagreement between the two justices can be found in their sparring opinions in District of Columbia v. Heller. The back and forth include Justice Scalia’s line in the majority opinion,

“Justice Breyer’s assertion that individual self-defense is merely a “subsidiary interest” of the right to keep and bear arms, see post, at 36, is profoundly mistaken”

and Justice Breyer’s statement in dissent,

“As important, the majority’s decision threatens severely to limit the ability of more knowledgeable, democratically elected officials to deal with gun-related problems. The majority says that it leaves the District “a variety of tools for combating” such problems. Ante, at 64. It fails to list even one seemingly adequate replacement for the law it strikes down.”

Which justices will have the most disagreement on the current Court? One pair worth watching is Justices Ginsburg and Gorsuch when Justice Ginsburg authors the majority opinion and Justice Gorsuch dissents.  We have already seen this twice – in Perry v. Merit Systems and Artis v. District of Columbia.  These cases are an early indication that these justices may have significantly different views in fundamental areas of law.  This pair has also had notable disagreements in oral argument.  While the breadth of the disagreement between these two justices may be dependent on how long 84-year-old Justice Ginsburg stays on the Court, she has signaled her intention to remain on for the time being.  If this is the case, we might very well see more Gorsuch dissents from Ginsburg opinions in the future.

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