Just how good is empathy after all?

Is empathy a good thing in judges? I would say that the answer is yes -- but that's not because it always leads judges to wise decisions, or specifically to liberal ones. If there were any doubt about these qualifications, here's the penultimate paragraph from Justice Scalia's opinion in Arizona v. United States, decided by the Supreme Court on June 25, 2012 (and available here). He writes:

        As is often the case, discussion of the dry legalities that are the proper object of our attention suppresses the very human realities that gave rise to the suit. Arizona bears the brunt of the country's illegal immigration problem. Its citizens feel themselves under siege by large numbers of illegal immigrants who invade their property, strain their social services, and even place their lives in jeopardy. Federal officials have been unable to remedy the problem, and indeed have recently shown that they are unwilling to do so. Thousands of Arizona's estimated 400,000 illegal immigrants--including not just children but men and women under 30 -- are now assured immunity from enforcement, and will be able to compete openly with Arizona citizens for employment.

This is the language of empathy, here directed to Arizona citizens' feel[ing] that they are "under siege by large numbers of illegal immigrants." While Justice Scalia asserts that the human realities he portrays so forcefully are not "the proper object of our attention," it is hard not to sense that in fact those realities do occupy some part of his attention. Advocates of empathy in judging would not complain of this, though apparently Justice Scalia himself might. But the familiar point that Justice Scalia's words vividly illustrate is that the impact of empathy on judicial decisions depends on who the judge empathizes with.

Even those who see empathy as a legitimate, or integral, part of judging likely agree that there is a point at which a judge's empathy obscures his or her judgment. Was that true here? It is clear that Justice Scalia is very angry about the majority's decision; he ends his opinion by saying that if Arizona can't do what it was trying to do in this case (which he describes as "securing its terrritory" and "protect[ing] its sovereignty"), then "we should cease referring to it as a sovereign State." He also refers at some length, both in the passage I've quoted above and earlier, to the President's decision not to enforce the immigration laws against a class of people who came to this country when they were under 16 (and, the point Scalia refers to in the quotation above, are not yet over 30 years old) -- a decision that was not directly at issue in the case and that was made, as Justice Scalia notes, after the case was argued to the Supreme Court. I am not sure how to measure whether any of this reflects too much feeling on Justice Scalia's part, and I'm pretty confident we could find similarly outspoken comments in the opinions of some of the great liberal justices of the past.

But in saying I'm not sure about this, I don't mean to dismiss the question. It seems to me that those (like me) who do approve of empathy in judging need to find a way to discuss, and then if possible measure, when empathy does distort judgment. Is the issue simply a matter of quantity -- too much of a good thing? Or is the quantity of empathy important only in the context of the structure of the rest of the empathetic judge's character -- so that some judges can be thoughtful and empathetic, while others can only manage one or the other? Or are there forms of empathy that support judgment and others that interfere with it? All these and no doubt other questions arise, and call out for answers, once we acknowledge (correctly) that judging isn't simply an exercise in objective reasoning.