Justice Jackson is the first justice in recent times to enter a Court with a clear six justice bloc in the majority. Unfortunately (for her) she is in the minority of this grouping.  In the first week of oral arguments this term Jackson more or less solidified her position on the left of the Court with her questions concerning Alabama’s redistricting plan in Merrill v. Milligan (many of her questions could be juxtaposed with those from Alito and others on the right of the Court).

There are two ways we can try to gauge how Jackson will fit into the Court’s current dynamic. First is through comparisons to current justices first terms on the Court (since Justices Alito and Gorsuch started towards the end of the 2005 and 2016 terms, there first terms were 2006 and 2017 for these analyses).

One useful metric is frequency in the majority. In their first terms the top justices’ frequencies in the majority were Roberts at 90.91% and Barrett at 88.64%. At the bottom were Thomas at 76.4% and Kagan at 75.51%.

The number of decisions per term has dipped since Justice Thomas joined the Court in 1991. The following graphs shows the number of votes in signed opinion from the justices in each of their first terms on the Court.

We can look at vote splits of the majority opinions the justices authored to give us some insight into where they fall on the Court’s voting balance.  Unanimous opinions tend to show less contentious cases. We might expect justices often in dissent to author these opinion types. Sotomayor authored the most of these of the justices with four in her first term.   Gorsuch and Barrett were at the bottom with one unanimous opinion apiece in their first terms on the Court. Jackson should be at the higher end of unanimous opinion authorship this term unless she tends to join dissents authored by her fellow progressive justices.

Interestingly when we look at written dissents for justices in their first terms, we have conservative justices at both ends of the spectrum.  Thomas had the most written dissents with seven in 1991, while Kavanaugh had the fewest with two in 2018. Still, we might expect Jackson or a combination of Jackson, Sotomayor, and Kagan to be at the higher end of dissents this term.

Concurrences also provide a comparison metric. We expect more concurrences from justices who are frequently in the majority, but who have an established jurisprudence which is unique from other justices who they aligned with ideologically. Based on this account we might expect few authored concurrences from Justice Jackson this term. Thomas, one of the Court’s most frequent author of concurrences had the most of the current justices in his first term.

Perhaps the most useful gauge is the other more progressive justices’ decisions last term, when there also was a 6-3 conservative majority. Based on the 58 signed opinions last term Justice Kagan was in the majority 69% of the time while Justice Sotomayor was in the majority 58% of the time. Although decisions by one vote were not as consequential with a 6-3 majority, Justice Kagan authored two while Justice Sotomayor authored one. For unanimous opinions Justice Kagan authored three and Sotomayor two.  For dissents Sotomayor authored 13 and Kagan authored seven.

In all likelihood Justice Jackson’s numbers will look more like Kagan’s from this past term. We still need time to find where she sits on the ideological spectrum but as Kagan is more moderate than Sotomayor and Jackson is now in her first term, we might expect Jackson to establish herself on the Court before yielding to a more ideological disposition (if in fact she does so).  This is typical for justices in their first few terms. Also, Sotomayor has been the furthest justice on the left for some time now and it is likely that Jackson will end up filling the ideological space between Kagan and Sotomayor in the future.