Future Composition of the Supreme Court

Yesterday I published a blog post evaluating the likely impact if Rick Perry were elected president.  In it I expressed a view on the likely impact of the President on the Supreme Court.  After completing a detailed analysis of the supreme court using biographical information in conjunction with a life table from the Social Security Administration, I have changed my mind on this subject.

The composition of the Supreme Court is slightly more likely than not to become more liberal in the event that Barack Obama is re-elected, which in turn seems more likely than not.  Note that this does not mean that the two events both taking place is more likely than not.  The betting market is giving Barack Obama only a 56.7% chance of winning.  In conjunction with the 55% chance that he has of successfully changing the court's composition in the event that he is re-elected this yields a 31% chance.  This is probably a bit low since it falsely assumes that he will need to win the presidency in order to change the court's composition.  There is always a chance that one of the conservative supreme court justices will retire or need to be replaced and that Barack Obama will then lose the election.

Also, since the table predicts mortality rather than incapacity or voluntary retirement, these results have to be taken with a grain of salt.  In addition they reflect average mortality for people with the age and gender of the Supreme Court Justices.  Since all of them are at least healthy enough to serve as Supreme Court Justices, we are interested in making predictions about a population that is likely to be healthier than the one described by the table.  These two effects bias the results in opposite directions, but it is possible that one will be greater than the other.

Note that if the Republicans win the next two elections and none of the liberal Supreme Court Justices retire or need to be replaced, the composition of the court is likely to become more conservative.  However, this will be harder to accomplish if one or more of the serving liberal Supreme Court Justices should retire or be replaced prior to Barack Obama leaving office.  Further, Republican victory in the next election is not the most likely outcome, and for them to win the following election would not be certain even if they were to win the upcoming one.