Logan Struther and Shana Kushner Gadarian have posted this draft on SSRN. Here is the abstract:

We examine the role that mass perceptions of the Supreme Court’s institutional nature—particularly how “political” it is—plays in assessments of its legitimacy. In a series of original studies, we find that policy disagreement with Supreme Court decisions leads individuals to view that decision, and the Court itself, as being political in nature. We then show that the more political people think the Court is, the less legitimate they consider it to be. In this way, we show that policy disagreement with decisions strongly and directly reduces Court legitimacy.