Trend Lines

The graph below displays the updated probability, after each new vote, of Chief Justice Roberts and Justice Alito being either the most conservative sitting justice or more conservative than former Chief Justice Rehnquist.

At each iteration, we learn more about Justices Roberts and Alito relative to the other justices. The solid trend lines plot the probability at each round that a given justice is the most conservative. The dashed lines represent the probability that the justice is more conservative than Chief Justice Rehnquist was.

As one might expect, Justice Alito's position does not change noticeably during the earlier votes because he was not casting votes at that time. His position does change slightly as our beliefs about the other justices change.

The next graph displays analogous information for Justice Sotomayor. The solid trend lines plot the probability at each round that Justice Sotomayor is the most liberal sitting justice. The dashed lines represent the probability that Justice Sotomayor is more liberal than was Justice Souter, whom she replaced. As with Justice Alito, Justice Sotomayor's position does not change noticeably until she begins casting votes, but does change slightly as beliefs about the other justices change.