Just came across this standing requirement, from several orders by Judge Mark Goldsmith (E.D. Mich.):
The Court prohibits the use of excessive footnotes in briefs. A brief supporting a motion or response may not contain more than 30 lines of footnotes. A brief supporting a reply may not contain more than 15 lines of footnotes.
Of course, this is just one judge's formal position, but my sense is that many judges informally take a similar view. Here's my general view for briefs (not for articles), though again others may disagree (and much depends on what you know about the preferences of the particular judge, or the particular multi-member court):
- If something is important, it should be in the text. If something is not important, it should be out of the brief altogether.
- Citations to cases, statutes, and other legal authorities (including treatises) are the most important part of the brief, not the least; they should be in the text.
- Citations to newspaper articles, web sources, and law review articles, on the other hand, tend to be both less significant and longer and thus more intrusive. Those are sometimes worth putting in the footnotes.
- String citations that are there just to confirm that the body of law you call solid really is solid might be worth putting in the footnotes (to support the key citations in the text)—though they might often be worth just deleting.
- Occasionally, there is a tangential detail that needs to be covered just for the sake of completeness, but that you think the court is very unlikely to actually care about. (This could, for instance, be some fact or procedural detail or procedural counterargument that the other party hasn't raised yet but that a curious reader might be thinking about.) That might be worth putting in the footnote, though think twice about it.
The rules are different for law review articles, partly because the functions of such articles are generally different and partly because the readers' expectations are generally different. But for briefs, footnotes are usually best minimized.