Causation is an important issue in many cases in a variety of fields of law and has been so for centuries. Yet it continues to confuse lawyers, in part because of a proliferation of unhelpful terminology (for which we judges must accept a good deal of the blame). In the space of three-and-a-half pages in the government’s brief, we find the following causal terms: proximate cause, actual cause, direct cause, but-for causation, contributing causation, contributory causation, significant causal connection, sole cause, factor in the victims’ injuries, concurrent cause, meaningful role, possible cause, remote cause, and cause in fact. Black’s Law Dictionary (8th ed. 2004) lists 26 terms in the entry for “cause.” The prosecutor was unable at oral argument satisfactorily to differentiate or explain the causal terms listed in his brief, or the three causal terms added to the instruction—“a factor that resulted in,” “primary cause,” and “played a part.”As you might guess, the Seventh Circuit went on to hold that the additional terms were likely as clear as mud to the jury. (H/t How Appealing.)
... Why was the prosecutor the one arguing the case on appeal? I suppose there's some value to having someone who was at trial, but appellate-advocacy skills are not the same as courtroom skills.