The Supreme Court is not an institution with regular turnover.  Since the Justices have life tenure, many stay on well into old age and often for decades.  The Justices are insulated in their positions for life and there is little incentive to move to other jobs.  In fact, the last Justice to leave the Court for a position outside the federal judiciary was Justice Goldberg in 1965.

In any case forty-nine Justices exited the Court between 1900 and the present.  Thirteen of these departures were due to death while the remainder were voluntary.  As Justice Kennedy completes his twenty-ninth term on the Court he has much to ruminate over.  He is already into his eighties and has played a significant role in many decisions that have dynamically shifted the national legal landscape.  Starting some time ago, Court watchers such as Above the Law’s David Lat reported on the possibility that Justice Kennedy was planning for an upcoming retirement.  This rumor has persisted as we close in on the end of the Court’s 2016 term. While many accounts look at anecdotal reasons for the potentially impending departure, there are also historic trends that support such a proposition.  Still, there are strong and persuasive reasons for Justice Kennedy to remain on the Court for the time being.

Expecting a Retirement

In the past death was often the reason that Justices left the Court. Under recent Chief Justices this has not been the norm.  While thirteen Justices died while in office from 1900-2016 (really 1914-2016 as Justice Lurton was the first active Justice that passed away during the 20^th century), only two Justices, Rehnquist and Scalia, passed away while still officially active members of the Court since 1954.  This is a dramatic shift from the eleven Justices that died while still active Justices between 1914 and 1954.  Comparatively, thirty-six Justices have retired from the bench since the turn of the 20^th century.

At 80 years of age and as the second oldest member of the Court, Justice Kennedy is well beyond the average age for Justices to leave the Court.  For the Justices that departed since 1900, the average age Justices have retired is approximately 71 while the average death age for Justices that died while active members of the Court is 67.  These two averages are marked in red in the following figure.

For this same set of Justices, Justice Kennedy is also older than the average age of death for Justices whether or not they were still active on the Court.   This average age is just over 77. 

Not Just Age

Justice Kennedy has also been one of the longest sitting Justices.  Looking at the Justices that have had the longest tenure of those who have departed since 1900, Justice Kennedy would place seventh if he retired at the end of the term.  This is shown in the next figure where the Justices’ time on the Court is graphed on the left and their age departing the Court (with Justice Kennedy’s age at prospective point of departure) is graphed on the right.

While Justice Douglas was the longest sitting Justice, he was on the Court for only eight more years than Justice Kennedy will have sat on the Court at the end of the term.  Suffice it to say Justice Kennedy has spent more time on the Court than one might expect from the average Justice. 

Why is June the likely month for retirement? First of all the Supreme Court term ends in June. Justice Kennedy would do his fellow Justices the service of not likely leaving his seat vacant for much of an active term if he vacated at the end of a term rather than somewhere in the middle.  The practice of vacating in June has also been the overwhelming choice for modern retirements.

Looking at the plot of modern retirements (those since 1900), more Justices have retired in June than in any other month.  This at least alludes to a strong possibility that any Justice choosing to retire would do so in June of a given year.

Strategy in Leaving

As Justices’ jobs on the Court are more or less assured moving forward at the point of confirmation, it may not be surprising that they want to dictate the terms on which they leave the Court.  Ironically, Justice (Thurgood) Marshall who left the Court just a few years after Justice Kennedy was confirmed purported to convey his disdain for the possibility of retiring during the Reagan presidency just years prior to retiring (captured in the final sentence of the link).  As Justices care about their legacies they may wish to leave when they can expect the sitting president to appoint a likeminded Justice.  As an aside many expected Justice Ginsburg to retire under President Obama for just this reason.

One way to draw similarities in policy preference is through voting behavior over time.  Both the Martin Quinn Scores (for Justices) and the Nominate Scores (for Congress and the President) are based on prior voting behavior.  Although they are not on the same scale, we can look at the Justices’ and Presidents’ relative placement on their respective scales for ideological congruity since they are both left/right or liberal/conservative spectrums.  In the Figure below, essentially when the bars for the Justices and the Presidents they departed under look the same we can assume similarity while when they are opposite we can assume polarity in preference.  One caveat in this figure is that although we have recent data on Justice Kennedy’s voting behavior there are no Nominate Scores yet for President Trump.  For the purpose of this figure I hypothetically estimated his ideology as the midpoint on the conservative end of the spectrum.  This could be adjusted though depending on President Trump’s actual ideology based on his votes.  Also since the Martin Quinn Scores go back to 1937, no Justices are on this chart that departed the Court prior to 1937 or that left before the FDR Presidency.

The Justices’ placement on the chart is drawn from their ideology score during their final term on the Court while the President’s is based on the term of Congress that coincided with the Justice’s departure.  Based on this figure it may not be in Justice Kennedy’s best strategic interest to leave at the current time if he wishes a likeminded Justice to fill his seat.  While he surely would not be the most polarized Justice with the sitting President (that award would go to the combination of Justice Douglas and President Ford), Justice Kennedy has skewed liberal over the past several terms and so based on voting preference alone he may wish to depart under a more moderate President (assuming President Trump falls at the mid-conservative point on the ideological scale or to the right of it).

Other Strategic Implications

Beyond the ideological implications of leaving at the end of the term, there are other factors that favor Justice Kennedy remaining on the Court.  Going back to the legacy point, Justice Kennedy is often described as the most powerful Justice because he is often the median or swing vote who decides cases where the Justices break down into clear conservative and liberal blocs.  This creates a power vacuum for Justice Kennedy to fill and may be an incentive for him to remain on the Court.

Much of the recent debacle over confirming a Justice after Justice Scalia’s death was predicated on where the Court’s median would lie next. With an Obama nominee like Garland, the Court would indubitably have shifted left and the median vote would no longer have been Justice Kennedy’s.  With Justice Gorsuch’s confirmation, however, many speculate that Justice Kennedy will retain the median slot as Justice Gorsuch is not expected to vote in a dramatically different fashion from his predecessor.

Even if Justice Kennedy had planned on retirement at the end of the term, President Trump’s recent moves may have swayed him in the other direction.  Justice Kennedy, for instance, is engaged with the international legal community at a time when President Trump appears to take an isolationist stance.  President Trump’s particular policy choices on issues ranging from immigration to voting may not align with Justice Kennedy’s true beliefs.  Any of this could be sufficient to keep Justice Kennedy on the Court for a bit longer.

Added speculation that President Trump has tried the carrot approach to removing Justice Kennedy from the Court for a more conservative jurist should only enhance Justice Kennedy’s desire to stay.  From the implication that Justice Gorsuch, a former clerk of Justice Kennedy’s was nominated, at least to some extent, for the purpose of persuading Justice Kennedy that it was time to leave the Court to other similar suggestions, Justice Kennedy may be wary of the current administration’s reasons for potentially wanting him off the Court.

In the end, only the people that Justice Kennedy has confided in know his true intentions. Based on available evidence, even though many cards point towards this as an ideal time for Justice Kennedy to leave a Supreme Court, there are strong reasons for Justice Kennedy to try to stay on the Court through the next presidential election.  When these two lines of reasoning are combined, there appears to be sufficient rationale for Justice Kennedy to remain on the Court, at least for the near future.

On Twitter: @AdamSFeldman

Post previously specified Justice O. Roberts was the last Justice to leave the Court to take another position.