The Supreme Court is not split Republicans verses Democrats. There is however an ideological split, which influences their decisions. This is all highly simplistic, as I don’t want a blog about textualism, or judicial activism ideas. I consider Ginsburg, Breyer, Sotomayor, and Kagan to be in the liberal camp and Thomas, Alito, Roberts, Kennedy and Gorsuch to be in the conservative camp. So, in theory, every decision will be decided by the group of 5 in the conservative camp. Wrong, wrong and wrong!
I’ll start with my conclusion. Liberals tend to stick together more than conservatives, at least in the current term in the Supreme Court, so if the liberals can attract one or more conservatives, then they will prevail. Sometimes, liberals join with conservatives. There are unanimous decisions, where ideological differences are unimportant. The most recent case, the New Jersey State Gambling case, was a 6 to 3 vote, with Kagan, normally on the liberal side, voted with the conservatives.
This is different from politics, where a Republican who supports a Democratic bill, in a close vote, is likely be pressured to change his vote.
I use Scotusblog.com in the current term for my statistics. Here is the agreement of votes from the liberal block, in the range of 96 to 100% agreement.
Ginsburg and Breyer 100%, Ginsberg and Kagan 96%, Ginsberg and Sotomayor 100%, Breyer and Kagan 96%, Breyer and Sotomayor 100%, Sotomayor and Kagan 96%.
The conservatives block of 5 justices, range from 68% to 100% as follows:
Thomas and Alito: 100%, Thomas and Roberts 68%, Thomas and Gorsuch 81%, Alito and Roberts: 75%, Alito and Gorsuch 81%, Alito and Kennedy 86%, Roberts and Gorsuch 85%, Roberts and Kennedy: 89%, Kennedy and Gorsuch 81%.
There was a lot of talk about Kennedy being the swing justice. But, a very good argument can be made that Roberts is also a swing justice. In fact, Roberts has agreed with Ginsburg and Sotomayor the same percentage of the time (68%) as with Thomas. Gorsuch is the new justice, and statistics show he sides with the liberals at times.
There are some important caveats to this. First, this is all cases, and not broken down in ones where there was an ideological difference. I don’t know how many cases were involved in calculating these statistics; it may be quite a small set. Finally, in a number of cases, justices concur in part, but not in all of the decision. The statistics don’t distinguish between partial or full agreement. Both cases are considered agreement.
The Supreme Court has to make judgement on the most difficult cases. It decides each case on its merits, and in relationship to the law. It has been noted that the Supreme Court is producing less opinions in the current term. It may be that Roberts has tried to obtain more of a consensus among the justices, by keeping the opinions more narrowly focused in some of the cases.
US Supreme Court Opinions (Recent slip opinions)
The Supreme Court always provides their legal reasoning for their opinions, and dissents, soon after a decision is rendered.