> My evidence is that the vast majority of Supreme Court decisions are either unanimous (when they don't represent an ideological issue) or along party lines (when they do).
I don't think that's a valid argument -- there are obviously differences in judicial philosophy that incline judges toward better apparent with one political faction or another, and non-unanimous rulings usually reflect different judicial philosophies.
> If they were really "applying their own idiosyncratic interpretations of the constitution", we would see a wider variety of votes.
No, you misunderstood. I was accusing those arguing that jurisprudence is politically motivated of looking at things through the lens of their own idiosyncratic interpretations of the constitution. We don't want the justices on the court doing this.
> I do not doubt that the vast majority of Citizens United discussions are of no merit -- that applies to practically every discussion. But you can find a scholarly disagreement in the decision of four Supreme Court members -- all of whom were nominated by the opposite political party.
No, I'm not claiming that discussions themselves have no merit, but rather that critiques of the ruling in public discourse are often based on factually incorrect assumptions about what the ruling involved.