I've just posted a new paper on SSRN entitled, "Should They All Just Get Along? Judicial Ideology, Collegiality, and Appointments to the Supreme Court of Canada".  My coauthor, Andrew Green, and I argue that the singular focus on the policy preferences of Supreme Court justices is apt to miss an important dimension of Court dynamics--the degree to which the justices engage in cooperative decision-making.

Here's the abstract:

Over the past 25 years, the justices of the Supreme Court of Canada have not exhibited the divergent policy views along party lines that have been characteristic of the justices of the United States Supreme Court. This apparent lack of partisan polarization in Canada may at first give rise to smugness about the appointments process in Canada; after all, our process appears to have successfully sidestepped the politicization associated with the US nomination and confirmation system. However, before any claim that the Canadian appointments process is in fact superior can be made or defended, it is necessary to understand what these findings imply about the judicial decision-making process and quality of adjudication by our Court relative to the US Supreme Court. In this paper we argue that whether the relative nonpartisan nature of the Supreme Court in Canada is advantageous depends on a number of assumptions surrounding the nature of the appointments process, the characteristics of justices who are appointed in each system, and the decision-making processes used by the justices on each Court.

This paper discusses the relationship between two potential determinants of a justice's votes: her personal policy preferences and the extent and nature of cooperation between justices on the Court at a given time. To set the context Part II briefly outlines the main findings of some recent empirical research on the judicial voting behaviour on the Supreme Court of Canada and compares it to similar empirical studies of the US Supreme Court. Part III then sets out a framework for analyzing the difference in voting patterns based on the extent to which a judge votes in accordance with her policy preferences and the extent to which the justices of a multi-member court can be characterized as cooperative. Part IV uses this framework to assess the different patterns of voting on the Canadian and US Supreme Courts and discusses the important normative tradeoff between deliberation ("positive" cooperation) and logrolling ("negative" cooperation). Finally, Part V briefly discusses the connection of this normative tradeoff to the appointments process, and identifies some additional considerations to guide future theoretical and empirical research.