Comment Re:This is informative how? (Score 2) 186
Assuming no relationship between decisions is ludicrous. On many items that aren't terribly controversial, Ginsburg and Scalia, for example, would rule similarly just because they are trained judges with a background in US law.
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I'd be really surprised if you didn't have a correlation between how one particular justice votes and how the rest of the justices vote.
Exactly. (PDF)
TL,DR:
Last Supreme Court term,
-Almost half of all Supreme Court decisions were unanimous
-The two Justices who disagreed most frequently in judgment were Ginsburg and Alito--and they still agreed with each other noticeably more than half the time (62.5%). Ginsburg and Scalia, in your example, agreed in judgment 65% of the time.
-That said, there is at least some truth to there being a "liberal wing" and a "conservative wing" (with Kennedy being the "swing vote"): of the 16 cases that were decided 5-4, 14 of them were Roberts-Scalia-Thomas-Alito vs. Ginsburg-Breyer-Sotomayor-Kagan with Kennedy casting the deciding vote. But a number of the lineups are more interesting.
The Justices are highly educated professionals, and as such agree with each other a lot of the time about what the law actually says. None of them is blindly ideological--but just the same, they do have their individual opinions about how the law should be interpreted, so some level of ideology is certainly present.