Even Best Friends Sometimes Disagree

Supreme Court justices' voting practices are fairly predictable. For instance, most decisions are unanimous. Since the longest serving justice on the Court, Justice Thomas, joined the Court in 1991, 42.65% of argued cases have returned unanimous votes. The Court also tends to reverse lower court decisions. The justices voted to reverse the lower court decision in 65.58% of decisions during the same period. The justices often vote within specific groups. These groups have been labeled conservative and liberal. While there is dispute within the legal community about the use of political monikers for judges, the justices' votes on issues before them often parallel those of traditional politicians within their respective voting blocs on similar issues. Within these groups, justices tend to vote in the same direction as specific justices more frequently than others.

While these patterns hold in most instances, the justices occasionally deviate from their traditional voting alignments. This raises the interesting question of why. What scenarios lead these frequent voting pairs to split from each other? These explanations and along with a specific justice-pair analysis are central to this article. Understanding these justices' reasoning in these cases helps to separate out fine-grained understandings of the individual justices by showing where we might expect them to deviate from one another in the future.

When voting pairs are the focus and votes are the unit of measurement, multiple convergent measures of voting behavior help generate interesting assumptions of voting pairs. The often used political science measure for voting behavior based on voting pairs is the Martin and Quinn (MQ) Scores. The MQ Scores were originally designed to explain the justices' voting behavior between 1953 and 1999. During that period, the MQ model predicted 74% of the justices' votes correctly which is a substantial improvement over the 65.58% of votes predicted correctly by always assuming the petitioner will always win. MQ Scores are dynamic in the sense that they vary from term to term. They have been updated through the end of the previous term and the numbers look as follows:

From this, we can determine that the most reliable conservative justice pairing includes Justice Kavanaugh with Chief Justice Roberts.

Additional evidence helps to solidify this point. Each term, SCOTUSBlog tracks this data for all pairs of justice. This gives us other baselines for understanding the justices' voting patterns. The voting alignment scores for each of the justice pairs listed above are as shown below:

Justices Kavanaugh and Roberts are the closest as they were in the exact same majorities for the 2021 Term (this of course assumes concurrences are considered votes in the majority which is necessary for Roberts's concurrence in the Dobbs case to be a vote in the same direction as Justice Kavanaugh's where Kavanaugh signed onto the Justice Alito's majority opinion). On the low end, both the Kavanaugh-Gorsuch pairings and the Roberts-Gorsuch pairings aligned 73% of the time.

The Differences

From when Kavanaugh joined the Court at the beginning of the 2018 term through the end of last term, Chief Justice Roberts was in the majority four times without Justice Kavanaugh (five times if we include this term's Helix Energy v. Hewitt) and Justice Kavanaugh was in the majority eight times without Chief Justice Roberts. Additionally, both justices were in dissent together in 12 decisions during this time. The four times Chief Justice Roberts was in the majority without Justice Kavanaugh prior to this term were in June Medical v. Russo, Dept. of Homeland Security v. Regents of the University of California, Department of Commerce v. New York, and Bostock v. Clayton County. Roberts was the swing justice with the liberals in all but Bostock, which was also joined by Justice Gorsuch (the decision in Dept. of Commerce v. New York had various sections with different majority configurations but the Roberts was joined by Kagan, Sotomayor, Ginsburg, and Breyer in section five which describes how the district court was warranted in remanding the case back to the agency).

All these cases were on closely followed by many and on the public's radar. They dealt with civil liberties including abortion, transgender rights, immigration, and the census question relating to citizenship. This term's Helix Energy was a lower stakes case when looking at the disbursed effects as it related to executive exemptions from overtime pay.

The array of cases where Justice Kavanaugh was in the majority without Chief Justice Roberts is more diverse. Although some regard Whole Woman's Health v. Jackson as a 9-0 or 8-1 decision, others regard the majority holding as a 5-4 decision with Kavanaugh in the majority and Roberts in dissent with the more liberal justices. The 5-4 majority decided that Texas officials could not be held liable for the enforcement of SB8 which allowed private citizens to file lawsuits for damages against anyone who "aids or abets" an abortion.

Aside from the obvious tension between Justices Kavanaugh and Roberts over abortion related issues, the other cases where Justice Kavanaugh was in the majority without Justice Roberts included cases ranging from criminal matters, to free speech, and patent/technology matters. These decisions also primarily did not come down to 5-4 splits and so there were a mix of the more liberal and conservative justices in the majority.

The only decision where Kavanaugh was a swing justice along with four liberal justices was in Apple v. Pepper, where Kavanaugh authored the majority opinion allowing iPhone owners that purchased apps through Apple's App Store to sue Apple under antitrust laws. The other 5-4 decision where Justice Kavanaugh was in the majority without Chief Justice Roberts was in Stokeling v. United States, which clarified the definition of "violent felony" under the Armed Career Criminal Act (ACCA) explaining that a sufficient degree of force was something more than the "slightest offensive touching." Along with Justice Kavanaugh, the Stokeling majority consisted of Justices Thomas, Gorsuch, Breyer, and Alito.

The other non 6-3 majority with Justice Kavanaugh in the majority without Roberts was in the 8-1 decision in Uzuegbunam v. Preczewski, which was also the only time in Roberts's history on the Court where he was the sole dissenter. The holding in Uzuegbunam provided the plaintiff nominal damages for campus officers stopping Uzuegbunam from speaking to students about religious beliefs on campus even when the campus policy later changed to allow such speech actions. In dissent, Roberts wrote that the case became moot after the change in the campus policy.

Justice Gorsuch was the only justice to vote in the majority with Justice Kavanaugh in all the other four instances. The first of these was Virginia Uranium v. Warren, where Justice Gorsuch authored the majority opinion joined by Kavanaugh, Thomas, Ginsburg, Sotomayor, and Kagan. The case dealt with federalism and specifically preemption where the majority held that the federal Atomic Energy Act (AEA) does not preempt a Virginia state-law ban on non-federal uranium mining.

The next was Van Buren v. United States. The majority opinion in that case was authored by Justice Barrett and along with Kavanaugh, the majority included Justices Gorsuch, Sotomayor, Kagan, and Breyer. The decision clarified what "exceeds authorized access" means under Section 1030(a)(2) of the Computer Fraud and Abuse Act of 1986.

In Ramos v. Louisiana, Justice Gorsuch authored the majority opinion which was joined by Justices Kavanaugh, Ginsburg, Sotomayor, Breyer, and Thomas. The majority held that the Sixth Amendment was incorporated to the states through the 14^th Amendment so that juries need to find criminal defendants guilty by a unanimous verdict for conviction.

The final 6-3 decision was in Iancu v. Brunetti, where Justice Kagan authored the majority opinion joined by Justices Kavanaugh, Alito, Ginsburg, Thomas, and Gorsuch. The case examined whether a clothing brand named "fuct" should be able to register a trademark under the Lanham Act which prohibits registration of "immoral" or "scandalous" marks. The majority held that these types of prohibitions against registration violated the free speech clause of the First Amendment.

Some Thoughts

No other justice pairs track as closely together as Justices Kavanaugh and Roberts during this period. Although Thomas and Alito are commonly identified as the farthest justices to the right on the current Court, since Kavanaugh joined the Court in 2018, Alito was in the majority 21 times without Thomas and Thomas was in the majority 15 times without Alito. Kavanaugh and Gorsuch voted together even less frequently as Kavanaugh was in 38 majorities without Gorsuch and Gorsuch was in 11 majorities without Kavanaugh.

Roberts and Kavanaugh are the most frequent justices in the Court's majority. Since Kavanaugh joined the Court, both justices were in dissent together on only 12 occasions. Alito also dissented in all 12 instances, Thomas dissented in six, Barrett dissented in two (of the three total where she participated), while Gorsuch dissented in two, Breyer in one, and both Sotomayor and Kagan in zero. Four of these cases where Gorsuch was in the majority with the liberals were in the area of tribal law while four others were in the area of criminal law (Borden v. United States, United States v. Davis, Concepcion v. United States, and United States v. Haymond).

This term so far, Kavanaugh and Roberts were in the two 5-4 majorities: Cruz v. Arizona and Bittner v. United States. Both majorities included diverse mixes of justices. Roberts was in the majority without Kavanaugh in the term's other split decision: Helix Energy v. Hewitt. If this is a sign of things to come, then we may see Roberts in the majority without Kavanaugh more frequently and in less high-profile cases. This, of course, will only be possible if Roberts can convince (or align with) at least one other conservative justice to join such majorities alongside him. In Helix Energy he had two, Gorsuch and Thomas, along with the three liberal justices to compose the six-justice majority.

Read more at Empirical SCOTUS....

Adam Feldman runs the litigation consulting company Optimized Legal Solutions LLC. For more information write Adam at adam@feldmannet.com. Find him on Twitter: @AdamSFeldman.