Many have described the Justices of the Supreme Court as “politicians in robes.” And from an outsider’s perspective, it certainly seems like liberal-conservative ideology predicts the way that judges will rule.
Eric Posner, a law professor at University of Chicago, says that in its upcoming decision on health care subsidies under the Affordable Care Act, the Court will be split liberal-conservative as a result of “motivated reasoning.” He explains that “how you interpret a text depends on your ‘priors’—the beliefs that you bring to the task of interpretation,” including your policy preferences. He also points out that “[i]n the case of the ACA, people who support the statute also seem to agree with the government’s interpretation of it. People who oppose the statute think that the government’s interpretation is wrong.”
Posner is among a number of scholars who have argued that judges’ decisions are best explained by their political preferences. I’ve always been sympathetic to this idea, but after conducting research on this question, I realize that the answer may be more complicated than we think.
My colleagues at Yale Law School’s Cultural Cognition Project and I have just completed a study called ‘Ideology’ vs. ‘Situation Sense’? An Experimental Study of Motivated Reasoning and Professional Judgment. This is exciting because it’s the first time judges have been tested for bias. We brought together hundreds of judges, lawyers, and non-lawyers to evaluate whether political ideology influences the way they interpret the “plain language” of a law, and compared the results.
For example, one of our prompts asked subjects to decide a case about whether leaving a sealed water bottle for someone to pick up later violated a law that prohibited “littering” or “depositing debris” in a nature preserve. The case came down to one question: Is a sealed water bottle “litter” or “debris”?
But there was a twist: We told half of the subjects that an immigrant-rights group left the sealed bottles of water in the nature preserve because they were expecting illegal immigrants to be crossing through the preserve on their journey from Mexico to the U.S., and wanted to make sure they had some water to drink. We told the remaining subjects that the sealed water bottle was left by construction workers building a border fence to stop immigration, and was left for other construction workers who were going to be at the site in the future.
Our theory was that, in deciding whether a sealed water bottle is “litter” or “debris,” it shouldn’t matter whether the bottle is left for an illegal immigrant or a construction worker—that is, unless personal views about immigration influence the way you read the language.
Here’s what we found: In deciding these specific legal cases, judges were far less influenced by their ideology than members of the public. In other words, whether a judge was personally inclined to support or oppose immigration made much less difference in whether he found the water bottle “litter” or “debris” than it did for a non-lawyer. For non-lawyers, personal beliefs about immigration heavily influenced whether they found the water bottle “litter” or “debris.” However, outside the context of a legal dispute, judges and non-lawyers were both influenced by their political ideologies in assessing how much risk is posed by controversial topics such as climate change and marijuana legalization.
So, our study shows that, compared to non-lawyers, judges are better able to set aside their political ideologies when they are deciding a legal case. We conclude that this is a result of professional training, which trains judges’ “pattern recognition” or “situation sense,” used to process legal arguments independent of their own ideologies. When non-lawyers look at the same questions without the same training, they tend to rely on their ideology to answer the question.
Note, though, that this is limited to the professional domain. When judges are operating outside their professional role—i.e., evaluating general risks of climate change and marijuana legalization—they are just as ideologically motivated as everyone else.
What is the significance of this study? It suggests that judges are more than “politicians in robes.” They employ professional tools to determine the outcome in a manner that is more systematic than voting according to their own policy preferences. Because non-lawyers are likelier to understand the issue as turning on political outlook, they are likely overestimate the extent that judges are also motivated by political bias when ruling on these questions.
Of course judges have strong ideas and disagree about how certain provisions of law should be interpreted (i.e., should the Constitution always be interpreted in a way that maximally preserves state power?) or what strategies should be used to decide certain cases (i.e., should you look primarily at the “plain meaning” of the text or the purpose of the law?). But that is different from asserting a policy preference or political affiliation; these are disagreements over reasoned theories about how legal institutions should operate.
There are limitations to how broadly our study’s findings can be generalized: We did not test a constitutional question, for example, and it is possible that constitutional questions tend to generate more disagreement between judges, as they may allow more room for judges to apply their different theories about how legal institutions should operate. We also tested state court judges, and it may be said that our findings are not generalizable to the Supreme Court, which some argue is more political than other courts.
Despite these limitations, our findings make me somewhat hesitant to accept the common claim that the Court’s rulings in the upcoming decisions on same-sex marriage, the Affordable Care Act, and other politically sensitive cases will be the result of the Justices’ political preferences.
Danieli Evans is a senior fellow in constitutional studies at the National Constitution Center.
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