WASHINGTON — When Chief Justice John G. Roberts Jr. and his colleagues on the Supreme Court left for their summer break at the end of June, they marked a milestone: the Roberts court had just completed its fifth term.
In those five years, the court not only moved to the right but also became the most conservative one in living memory, based on an analysis of four sets of political science data.
And for all the public debate about the confirmation of Elena Kagan or the addition last year of Justice Sonia Sotomayor, there is no reason to think they will make a difference in the court’s ideological balance. Indeed, the data show that only one recent replacement altered its direction, that of Justice Samuel A. Alito Jr. for Justice Sandra Day O’Connor in 2006, pulling the court to the right.
There is no similar switch on the horizon. That means that Chief Justice Roberts, 55, is settling in for what is likely to be a very long tenure at the head of a court that seems to be entering a period of stability.