The Supreme Court chart visualizes the timelines of justices on the Court as a river, flowing up when there are more appointees by Republican presidents and flowing down with more Democratic appointees. (We take significant liberties with justices before the establishment of those two parties, aligning Democratic-Republicans with Democrats and aligning Whigs and Federalists with Republicans.)
We know that many current observers view the progression of the Court through a partisan lens, assuming that Republicans aim to make a more conservative Court while Democrats seek to appoint more liberal members.
Ideology has always played a role in appointments, but our research proved that history is messy. We did not have an external measure of Court ideology that ran the whole period, but we did include as an inset a measure from 1939 to present day.
It is certainly interesting to note that the Court has at times had nine Democratic appointees or nine Republican appointees, but that the most liberal and most conservative landmark decisions do not necessarily correspond with those periods. We think the demonstrated variation over time in partisanship on the Supreme Court is a compelling component of our Timeplot. What do you think? How would you revise this for future versions of this Timeplot? Leave your comments.
Although of course liberal-conservative measures are imperfect, I would like to see something that actually plots the ideological estimates for individual justices over time. At the moment, the individual lines (which show seat-by-seat continuity) don’t reveal anything about where the justices stand. It would be interesting to be able to see visually, for example, whether the data sources you use support Justice Stevens’ recent claim that all of the justices who were on the court with him when he was first appointed would have agreed with the dissenters in Parents Involved.