Mr. Ed, Friend of the Court:

Some people have faulted the ACLU for failing to file friend-of-the-court briefs (also known as "amicus briefs") in certain free speech cases -- this, they've argued, shows that the ACLU doesn't really support free speech, at least of the sort involved in those lawsuits (for instance, religious speech). I've blogged before about why this is wrong, but I'd like to elaborate on this further, because it might help people understand the proper role of amicus briefs.

When are groups supposed to file amicus briefs? Not just when the case involves something that the group cares about; rather, they're generally supposed to do it only if they have something valuable to add that the parties and that other amici aren't already saying. This is what my two favorite public interest law firms, the libertarian Institute for Justice and the conservative-libertarian Center for Individual Rights (which in turn credits IJ), call the "Mr. Ed rule." Here's Scott Bullock from IJ:

We have long followed what we call the "Mr. Ed" rule on amicus briefs. . . . Mr. Ed (the talking horse) only spoke "when he had something to say." And that is our approach. We don't do amicus briefs unless we feel like we can bring a unique perspective, voice, or insight into the case. . . .

And here's Michael Rosman of CIR:

[W]e prefer to be involved in a case by representing parties. Accordingly, our official policy is that we file amicus briefs infrequently, and only if we believe that we have something to say that is of interest and that will not be said by the parties to the litigation. . . .

That's (1) a sensible allocation of the group's resources; amicus briefs take time and effort to produce, and most public interest organizations are already stretched pretty thin. But (2) it's also how courts ask groups to behave.

That's made explicit in Rule 37.1 of the U.S. Supreme Court Rules:

An amicus curiae brief that brings to the attention of the Court relevant matter not already brought to its attention by the parties may be of considerable help to the Court. An amicus curiae brief that does not serve this purpose burdens the Court, and its filing is not favored.

Rule 29 of the federal Rules of Appellate Procedure, which applies to the federal courts of appeals, likewise states:

The motion [for leave to file an amicus brief] must be accompanied by the proposed brief and state . . . the reason why an amicus brief is desirable and why the matters asserted are relevant to the disposition of the case.

The Advisory Committee notes accompanying the rule make clear that "relevance" refers to the same standard as that given in Supreme Court Rule 37.1. ("The former rule only required the motion to identify the applicant's interest and to generally state the reasons why an amicus brief is desirable. The amended rule additionally requires that the motion state the relevance of the matters asserted to the disposition of the case. As Sup. Ct. R. 37.1 states: 'An amicus curiae brief which brings relevant matter to the attention of the Court that has not already been brought to its attention by the parties is of considerable help to the Court. An amicus curiae brief which does not serve this purpose simply burdens the staff and facilities of the Court and its filing is not favored.' . . .")

Now sometimes groups do file briefs just because they feel a burning need to participate in a case -- perhaps because they want to impress donors, or because they think their very name might help influence the judges. But that's not what courts really want them to do, and it's both expensive and possibly counterproductive (since judges might get annoyed when they feel that a group is wasting the judge's time by filing briefs that add nothing really new). It also wastes the time of lawyers on the other side, who have to read the briefs closely and figure out whether they indeed have anything to say.

So keep that in mind when you're criticizing a group for not filing an amicus brief. If you can find evidence that, for instance, the ACLU failed to file an amicus brief in a religious speech case because it thought religious speech shouldn't be protected, you can certainly fault the ACLU for having such a mistaken view. But the ACLU's failure to file an amicus brief does not by itself reveal the ACLU's substantive views: It may well be that Mr. Ed just didn't think he had anything really helpful to say.