This is probably the most important question facing legal scholars today and throughout history. A group of researchers has concluded: "the results most supported the position that professional judgment imparted by legal training and experience confers resistance to identity-protective cognition — a dynamic associated with politically biased information processing generally — but only for decisions that involve legal reasoning."
'Ideology' or 'Situation Sense'? An Experimental Investigation of Motivated Reasoning and Professional Judgment by Dan M. Kahan, David Hoffman, Danieli Evans, Neal Devins, Eugene Lucci, and Katherine Chengó.
"This paper reports the results of a study on whether political predispositions influence judicial decisionmaking. The study was designed to overcome the two principal limitations on existing empirical studies that purport to find such an influence: the use of nonexperimental methods to assess the decisions of actual judges; and the failure to use actual judges in ideologically-biased-reasoning experiments. The study involved a sample of sitting judges (n = 253), who, like members of a general public sample (n = 800), were culturally polarized on climate change, marijuana legalization and other contested issues. When the study subjects were assigned to analyze statutory interpretation problems, however, only the responses of the general-public subjects and not those of the judges varied in patterns that reflected the subjects’ cultural values. The responses of a sample of lawyers (n = 217) were also uninfluenced by their cultural values; the responses of a sample of law students (n = 284), in contrast, displayed a level of cultural bias only modestly less pronounced than that observed in the general-public sample. Among the competing hypotheses tested in the study, the results most supported the position that professional judgment imparted by legal training and experience confers resistance to identity-protective cognition — a dynamic associated with politically biased information processing generally — but only for decisions that involve legal reasoning. The scholarly and practical implications of the findings are discussed."
"The most satisfactory way to overcome these limitations, we believe, is through valid experiments performed on judges. In this paper, we present the results of such an experiment. In it, judges, lawyers, and law students were instructed to assess legal problems that were designed to and did trigger unconscious political bias in members of the general public.
The experimental results furnished evidence strongly at odds with the conclusion that judges’ are influenced by [ideology?]. Judges of diverse cultural outlooks—ones polarized on their views of the risks of marijuana legalization, climate change, and other contested issues—converged on results in cases that strongly divided comparably diverse members of the public. Culturally diverse lawyers also displayed a high degree of consensus in their legal determinations. Law students, in contrast, did not: in addressing the legal problems featured in the experiment, they polarized along the same lines that divided the legally untrained members of the public, although to a lesser extent."
"These results strongly supported the hypothesis that professional judgment can be expected to counteract 'identity-protective cognition'—the species of motivated reasoning known to generate political polarization over risks and myriad policy- and legally consequential facts. Legal training and experience, on this view, endows judges and lawyers with a specialized form of cognitive perception—what Karl Llewellyn called “situation sense”—that reliably focuses their attention on the features of a case pertinent to its valid resolution. The results of our experiment support the conclusion that 'situation sense' is sufficiently robust to fix judges’ attention on such decision-relevant features of a case notwithstanding the tug of influences that might systematically focus the attention of the public on facts that are irrelevant and indeed inimical to impartial legal decisionmaking. Indeed, this dynamic, we surmise, creates a source of divergence between expert legal and nonexpert lay assessments of law akin to the divergence between expert and lay assessments of risk."
"But the results also support a conclusion that ought to be a matter of deep concern for the legal profession: that our system of justice lacks reliable practices for communicating courts’ neutral resolution of divisive matters."
Finally, David Hoffman, one of the authors of the study, has stated elsewhere, "I think the study speaks to something larger still — the value of legal education & experience in producing situation sense, which enables lawyers and judges (and, to a lesser extent, law students) to agree on the results of legal outcomes notwithstanding their political and ideological priors. Such legal judgment is, after all, one of the practical skills that law school conveys, and which it ought to boast about."