A reader asked whether I thought judges themselves knew the grammatical and mechanical rules I discussed in the last entry; even if they know, do they care? No, most don't know, and those who do don't care a bit. The importance of punctuation isn't to have the judge give tacit points for good grammar but to allow the judge the greatest understanding of your argument. Proper comma usage aids comprehension by setting off modifiers less directly related to the main message.
Sometimes failure to properly punctuate creates ambiguities. When nonrestrictive adjectival clauses beginning with relative pronouns like who, that, or which aren't set off (or restrictive ones are set off) the meaning the sentence conveys is not only confusing; it's quite wrong. Think about the miners who worked beneath the surface in the last entry and the distinctly different meaning that results from adding a comma. The creation of ambiguities when you wrongly punctuate relative clauses is another reason, besides cognitive ease, that teachers emphasize adjectival clauses.
Adverbial clauses don't create the same ambiguities because the initial words of adverbial clauses, like because, since, where, or when, always have the same grammatical role when they have the same sense: since introduces a restrictive clause in its temporal sense and a nonrestrictive one in its causal sense. At worst, incorrectly punctuating a since clause creates only semantic ambiguity, which the writer failed to enlist punctuation's aid to resolve, not relative-clauses' structural ambiguity.
Incorrectly punctuating adverbial clauses doesn't ordinarily create ambiguity, but it confuses the reader for other reasons. Consider this sentence from the preceding entry:
If someone asks, "Did the miners die, since the employer spent too little on safety" when employer underspending wasn't the reason, the question should elicit denial only of the "since" clause, not the whole statement.
More than a single punctuation error could mar this sentence, but I want to focus on the effect of incorrectly placing a comma after safety and before when. An adverbial clause introduced by when is usually restrictive, as it is above. Inserting a comma after safety causes the reader's brain to try to interpret what precedes when before reading the rest. The effort is misguided because the if clause speaks of the effect of someone's act of asking only on the condition that the employer's underspending wasn't the reason for disaster. A comma before when generalizes the conditional relationship. By triggering the wrong interpretive strategy, the writer risks confusing or at least delaying the reader.
Attorneys must overcome being conditioned in grade school to think of correct usage as a way to impress readers or avoid embarrassment. Law-firm partners will often incompletely extinguish their early conditioning because they aren't pressured to understand briefs under tight deadlines, and they are apt to speculate about whether correct syntax and mechanics "look right" or whether the judge will mistake right for wrong. Judges theorizing about what judges care about make this mistake — one hopes referring to other judges' reactions — as when Justice Scalia suggests avoiding contractions because of a some judges' possible disapproval. Judges lack the time or interest to correct attorneys' grammar. Safer to give judges what they need than what they say judges want.