I think there's a key distinction underlying Sunstein's post that needs to be brought out here: the difference between the relative political orientation of the Justices and the relative political orientation of the law. They are related, but they are not the same. To see the difference, consider a very highly stylized example. Imagine in Year 0 a majority of the Court is very far to the left, and and as a result key areas of law are pushed quickly to the left. Now imagine that ten years later, a majority of the Court is only moderately to the left, and that now the law is being pushed only slowly to the left.
So is the new Court "conservative" or not? It depends how you look at it. The net effect of the new Court is still to move the law to the left in key areas, just more slowly than before. At the same time, the political orientation of the Justices will have moved to the right: the new Court will be much more conservative than in the old days of Year 0. The result would be a Supreme Court that people call "conservative" even if the effect of the Court's decision is to move the law to the left. (To be clear, I'm not saying that this is exactly what happened with the Warren Court, and no, I'm not trying to endorse such a political view of the law; this is just an illustration to show the distinction.)
I wonder if this distinction explains why the public perception is different from what Sunstein suggests: my sense is that Cass is focused on the changing orientation of the Justices, whereas the common critique is more focused on the changing positions of the law.
I think there is a flaw in orienting yourself with respect to specific holdings. Instead I would draw your attention to several paradigms.
e.g., does the "footnote 4" philosophy guide the judge's interpretation of rights
Randy Barnett's "Lost Constitution" argued a paradigm based on whether the government bore the burden of proof under heighten scrutiny that a law was within the enumerated powers. In this sense, Breyer is by no means moderate and would not have been seen as such even in 1940.
Yes, I would say. It is to the left of the Warren Court, after all. What Commentor 1 is thinking, I suppose, is that lawyers and perhaps society generally are so far to the left now that the current Supreme Court is no longer to the left of the current society.