I think that at this point most ELS scholars are comfortable with the notion that attitudes play a crucial role in judicial decision making, even if that role varies by judge, by court, and even by case. The well-established importance of attitudes in judicial decision making leads to the question of where attitudes come from.
Social background theory argues that attitudes come from shared environmental influences, such as one’s father’s occupation, the region where one went to college, and other such factors. This model, though, almost certainly overstates the case of shared environmental influences. Psychologists and behavioral geneticists have been amassing evidence for decades now showing that the extent to which personality factors are influenced by one’s environment, they are largely determined by the idiosyncrasies experienced by the individual, and less so by the environmental factors that one shares, say, with a sibling. Evidence for this includes the findings that the correlation between unrelated siblings (i.e., adopted children raised as siblings in the same household) is fairly small. Alternatively, the correlation in personality among identical twins reared apart is fairly substantial. These and other twin-based studies suggest a substantial heritable component to personality.
Recent work by John Alford, Carolyn Funk, and John Hibbing reports similar findings for political attitudes (Hibbing and Alford, December 2004 Perspectives on Politics; Alford, Funk and Hibbing, May 2005, American Political Science Review). They report heritability effects on political attitudes ranging from .41 (school prayer) to .18 (support for federal housing assistance) with an average heritability coefficient across 28 political items of .32. The average effect for the unshared environment is a robust .53, but the effect for the shared environment (e.g., fraternal twins reared together) is only .16.
I provide here the heritability coefficients for other political attitudes likely to be of interest to judicial scholars:
Death Penalty .31
Gay Rights .28
None of this means that there are specific genes for these policies, but more likely, that there are combinations of genes that influence egalitarianism, openness to outgroups, a desire for order, etc., that in turn influence these attitudes.
Hibbing and Alford suggest implications of these findings for the criminal justice system, war, and the creation of political institutions. For those unfamiliar with their work, it's well worth reading.