The central thrust of my arguments and analysis to this point has been that the U.S. Supreme Court enjoys a broad and deep reservoir of goodwill that allows it to get it decisions – even controversial and unpopular ones – to stick. That has probably not been true of the Court throughout American history, and it is certainly not true of high courts throughout the world (since I live in Africa right now, the ruling of the high court in Niger is an interesting example of judicial impotence).

But is there anything at all that might undermine the legitimacy of the Supreme Court? Greg Caldeira and I believe we have found an instance in which the actions of interest groups are threatening to the Court’s legitimacy. This has to do with politicized processes of confirming nominees to the Court.

The country has witnessed politicized nominations in the past. The vote on Judge Samuel Alito’s ascension to the High Bench was one of the most divided in recent history. And in 2008, Justice Clarence Thomas reignited old passions with the publication of his memoirs and with the repetition of his famous characterization of the Senate proceedings as “a high-tech lynching for uppity blacks who in any way deign to think for themselves.” While I of course recognize that, at some level, every nomination to the Court is politicized given the stakes involved in controlling the ideological path of the Supreme Court, some nominations mobilize interest groups and the mass public while others do not.

A newly published book identifies some important threats associated with politicized confirmation processes. In Citizens, Courts, and Confirmations, Caldeira and I provide one of the first examinations ever of how confirmations processes shape the views of ordinary citizens.

Based on a nationally representative survey conducted prior to the nomination of Judge Samuel Alito to a seat on the high court, during the confirmation process, and well after the process ended, this analysis examines how citizens’ views of the U.S. Supreme Court were affected by the battle over whether Alito should be confirmed to a seat on the Court.

The most important conclusion of that work is that politicized confirmation processes can indeed damage the institution itself. That is, our study shows that the legitimacy of the Supreme Court was diminished over the course of the confirmation process. In this conclusion, we are not referring to attitudes toward Alito himself, but rather to attitudes toward the fundamental legitimacy of the Court itself.

The culprit seems to have been the advertisements run by interest groups, both for and against Alito’s confirmation. Groups were certainly active in this battle, spending more than three million dollars in trying to shape the views of the American people (and, by extension, the votes of the representatives of those people).

And our survey data indicate that people were indeed attentive to the ads run, for or against, with something close to two-thirds of the American people reporting being exposed to advertisements regarding whether Alito ought to be confirmed.

Most important, the willingness to extend legitimacy to the Supreme Court among those exposed to the ads declined from prior to the nomination to afterwards. Our surveys indicate that most Americans supported the nomination of Samuel Alito to the Supreme Court; but Americans who viewed the ads associated with his nomination came to have less faith in the Court itself.

Many of the ads run for and against Alito’s confirmation were decidedly political, the ads differ little from attack ads used in ordinary political campaigns. After seeing these ads, it would not be surprising that many Americans concluded that the Supreme Court is just another political institution, and as such, is not deserving of any special deference or respect. When the Supreme Court loses its special status as a “non-political” political institution in the eyes of ordinary people, the institution is weakened.

Any loss in the legitimacy of an institution like the Supreme Court is extremely significant, inasmuch as legitimacy is the principal political capital of courts. So if the legitimacy of the institution is diminished, then the efficacy of the institution is at risk.

We have some understanding of the process that likely lead to these results. The Supreme Court profits greatly when citizens view it as being “above politics,” because “politics,” in the contemporary American case is not a highly regarded vocation. When the Court is seen as different from other political institutions, engaging in principled, not self interested and strategic decision making, legitimacy attaches to the institution.

As I have argued, the lesson that judges are not “just politicians in robes” is taught via the highly accessible symbols of the legal process. When citizens pay attention to the Supreme Court, they are bombarded with these symbols of judicial uniqueness, and, as a consequence, judges are exempted from the disdain directed toward most ordinary politicians. So, if politicized nomination processes unteach the view that courts are different, institutional legitimacy suffers.

In its rulings on the regulation of campaign activities, the Supreme Court itself has stripped governments of most legal means by which the free speech rights of interest groups might be restrained, and perhaps that is appropriate. After all, the Supreme Court is an enormously important policy-making institution – not just a court that decides legal disputes between parties – so in a democratic society all interests ought to enjoy maximal opportunity to determine who will be making legal policy. A democracy could hardly do otherwise.

But perhaps groups themselves might understand that campaigns portraying the Supreme Court as just another political institution damage the authority of that institution. Because this is so, perhaps interested parties could exercise some restraint in their arguments, pro and con, regarding nominees to the high bench. I do not have any data on the effectiveness of politicized campaigns, although our survey reveals that the efforts of progressive groups to block Alito’s confirmation by painting him as excessively conservative clearly failed.

I understand that calling for restraint is likely to be just as effective as calling on ordinary politicians to eschew negative attack ads, which, presumably, are used because they are thought to be effective. But given the evidence of an impact on popular esteem for the Court, groups and their supporters should exercise restraint in how they fight battles over nominations.

This is not to say that groups should not try to convince the American people of the wisdom or folly of confirming a nominee to the Supreme Court. Americans understand what it means to be a judicial liberal or a judicial conservative, and debate on these ideological differences do not necessarily undermine judicial legitimacy. The American people accept that judges are policy makers, and must, perforce, rely upon their own ideological predilections in making their decisions.

Honest and open debate over issues of privacy, of liberty, or equality, or of security is not off-putting to the American people and therefore does not undermine judicial legitimacy. People disagree over the direction of legal policy, and those disagreements are appropriate and legitimate. Those differences, however, can be debated in terms more appropriate to a legal institution like the U.S. Supreme Court.

Putting ideology aside for a moment, all interests profit from a high court that can definitively decide very difficult issues of law and politics. To have the Supreme Court decide who would become president of the U.S. in 2000 likely had more beneficial consequences than having the House of Representatives select the president. The Supreme Court is a political institution but that does not mean that it is political in exactly the same sense as is Congress or the presidency. Undermining the Court’s authority is in the interest of no one.

My own research on state judicial elections has clearly demonstrated that discussions of legal issues by aspirants to a seat on a court do nothing to undermine the perceived impartiality of judges and the legitimacy of courts. The American people want to know the ideological positions of candidates for the state and federal bench on issues such as abortion, gun control, affirmative action, prayer, takings, etc., and few believe that judges who announce their positions on these issues cannot rule fairly and impartially from the bench.

At the end of the day, whether ordinary people extend legitimacy to courts rides on whether their expectations are met. Stealth candidates in an age in which courts are so obviously policy-making institutions seem to violate the expectations of most.

So discourse and debate on ideology are indeed possible without doing damage to the judiciary. Just as on this blog, there are comments that are reasoned, based on quite legitimate differences in views, and comments that are puerile and not worthy of replies. When it comes to courts and judges, we all profit from debate that is strong, but civil and respectful of legitimate ideological differences.