Measuring presidential influence

As we were creating our Timeplot of the history of the Supreme Court, we wanted to clearly display the influence of each U.S. president on the Court in an objective, non-partisan manner. To do this, we chose to measure influence by comparing the number of each president’s “justice days”—in other words, measuring how many days an appointed justice served (or in the case of recently-appointed justices, are predicted to serve) on the Court.

We created semicircle “bubbles” aligned to each president’s spot on the timeline and sized to each president’s total number of “justice days.”

Each half circle is colored by the president’s political party, so that it’s apparent at a quick glance that a few presidents have had an outsized ideological influence, at least by our objective measure. George Washington, Andrew Jackson, Abraham Lincoln, Franklin Roosevelt, Dwight Eisenhower, and Ronald Reagan have clearly outsized semicircles, indicating a high amount of influence on the Supreme Court of their day.

Of course, establishing a clear correlation between simply appointing justices and significantly affecting the Court’s ideology is tricky business—as Eisenhower’s appointments of the liberal Justices Warren and Brennan demonstrate, after being appointed to a lifetime term, a justice will not necessarily reflect the political preferences of the appointing president.