Where pertinent and significant authority comes to a party’s attention after briefing, or after argument, it may be brought to the court’s attention.
What qualifies. A decision issued after the brief was filed; authority overlooked and genuinely significant; a statutory amendment; or a development in a related case.
Form. A letter, promptly filed, with a reference to the page of the brief or the point of argument it concerns, and the reasons for the citation stated in a small number of words — federal practice caps the body at three hundred and fifty words.
No argument. The letter must not reargue the case. Letters that use the new authority as a vehicle for a supplemental brief are struck, and the practice irritates courts.
Response. The other side may respond promptly within the same limits.
Timing. Immediately. A significant decision cited a month after it issued suggests it was not thought helpful until the panel’s questions revealed otherwise.
After argument. Permitted and common, and a well-judged letter answering a question the panel asked, with the authority it sought, is among the more useful filings in appellate practice.
Adverse authority. Counsel must disclose directly adverse controlling authority not disclosed by the opponent, and this is the mechanism.