In a post about persuasive advocacy, the Sardonic Lawyer writes--
I've been thinking a lot lately about the poor job many attorneys do of limiting themselves to legitimate arguments on behalf of the client, as opposed to the "kitchen sink" approach I encountered quite a bit in practice. If, someday, I have the opportunity to teach an ethics course in law school, I think I'll dedicate at least one class to the practical question of distinguishing between zealous advocacy and shameless idiocy.
The post continues with a list of six rules to use to determine if a lawyer has crossed the line from advocacy to idiocy. It's well worth a read.
In practice, I think the Sardonic Lawyer's rules are most often violated when lawyers write briefs. It frequently happens, for example, when a low-level associate does a draft of a memorandum that necessarily includes every conceivable point, and then turns it in to a superior who has insufficient time for editing.
It also happens when lawyers don't want to let go of an argument because they think they might need it on appeal. This raises two other issues: Why preserve a weak argument? And is it necessarily waived if not included in a trial-level brief? Often that's not the case.