One of my honors advisees this term has just completed her thesis, an empirical examination of the ACLU's ability to influence the U.S. Supreme Court through filing amicus curiae briefs during the Burger and Rehnquist Courts. It's a careful study, combining qualitative and quantitative methods. The thesis has a number of interesting findings; I won't go into all the details, but I wanted to share this:
It's a plot of the odds ratio for the presence of an ACLU brief (from a series of justice-specific logistic regressions that also included a host of controls) where the outcome variable is a pro-ACLU vote. The vertical line at 1.0 corresponds to "no marginal association;" values less than one are negative associations, while values above one are positive. (I'm omitting the CIs because they make the plot very messy.)
The interesting thing, of course, is that justices widely perceived as more politically liberal also tend to be those that are most "influenced" by the ACLU's amicus briefs.
Also, to all those NYC firms out there: My advisee, Shannon Azzaro, will be starting law school at Fordham in the fall, with a focus on intellectual property. I understand that her 2013 summer is still free...