NEW: DC Circuit panel hearing arguments on Trump's presidential-immunity appeal on Jan. 9 tells parties to be prepared discuss "discrete issues" raised by amicus briefs.
One such brief argues that the immunity appeal is improper and must wait until after trial (an argument Jack Smith hadn't made).
As a non-lawyer, I can't speak to the argument made; but I would guess Jack Smith didn't make the argument because he'd rather any conviction be (relatively) final, without a bunch of extra litigation about immunity and the like.
