This article starts with a bit about Justice Scalia and then says this:
“While liberal justices are over all more supportive of free speech claims than conservative justices,” the study found, “the votes of both liberal and conservative justices tend to reflect their preferences toward the ideological groupings of the speaker.”
but then they get to the actual results:
The largest one, at least among members of the Supreme Court who cast more than 100 votes in free speech cases since 1953, belongs to Justice Scalia. Justice Clarence Thomas is not far behind. Chief Justice John G. Roberts Jr. and Justice Samuel A. Alito Jr. have not cast enough votes for a reliable appraisal, but the preliminary data show a similarly significant preference for conservative speakers.
Justice Anthony M. Kennedy, the current court’s most reliable free speech vote, favored conservative speakers by a smaller but still significant margin.
The Roberts court’s more liberal members “present a more complex story,” the study found. All supported free expression more often when the speaker was liberal, but the results were statistically significant only for Justice John Paul Stevens, who retired in 2010.
In the case of Justice Stephen G. Breyer, the difference was negligible. And it is too soon to say anything empirically meaningful about Justices Sonia Sotomayor and Elena Kagan.
In other words, the conservative justices are all much more likely to vote for free speech if it’s conservative while liberals only lean towards supporting liberal speech. Look at the numbers (they are the percent of time they voted for free speech if the speaker was liberal, if the speaker was conservative, and the total votes counted; an asterisk means the difference is significant):
Thomas 23.1* 65.4 104
Scalia 20.7* 65.2 161
Alito 9.1* 53.9 24
Roberts 15.4* 64.3 27
Kennedy 43.2* 67.7 143
O’Connor 30.6* 50.7 190
Breyer 40.0 38.1 87
Souter 60.3 51.1 103
Ginsburg 53.2 40.0 92
- Stevens 62.8* 46.9 260
You might notice that all of the conservative judges have a statistically significant difference and only one liberal judge does. You might also notice that the largest difference for a liberal judge is about 16%, while the smallest for a conservative judge is about 20% and that’s if we count O’Connor and Kennedy as conservative. If we count them as moderate, then the smallest difference for a conservative is about 39%–but both sides are the same.