He offers three reasons to favor the judges' view — "the 'halo effect'", "less is more", and "easy is better".
While Blawgletter agrees with each point, we also think Garner has hit on something more basic. It has to do with the most powerful way to appeal to an audience — ethos, or moral character.
The first point — about the "halo effect" — relates to what happens in a reader's mind when your writing deploys what Garner calls "clean, precise, crisp sentences". The reader notices your "professional care" and may even equate it (perhaps wrongly) with "substantive soundness."
Garner's "less is more" idea posits that a short-but-punchy brief can sway with swagger and avoid weak points that dilute the strong ones.
And "easy is better" means that "the ideal brief spares the judge any unnecessary effort, physical or mental." Long, tedious briefs tax judges' ability, and willingness, to grasp your points.
So far, so good. But do the three have a unifying theme?
Logos, pathos, and ethos
A fourth century B.C. Athenian can shed light on the question.
In Rhetoric, Aristotle (or his students) identified three kinds of appeals to an audience — logos (argument from reason), pathos (persuasion by means of emotional appeal), and ethos (convincing through the moral character of the speaker or writer).
Those of us who went to law school tend to think that a focus on reason (logos) ranks highest in the persuader's art. We also suspect that the messier business of playing on the audience's feelings (pathos) comes next. Your stature as a moral person (ethos) hardly counts at all.
Character trumps everything else
But that way of thinking about persuasion grossly overvalues the analytical skills that our law teachers imparted to us. As Oliver Wendell Holmes wrote, "[t]he life of the law has not been logic . . . . The law . . . cannot be dealt with as if it contained only the axioms and corollaries of a book of mathematics." You have to put life into the logic. Else it means nothing to people — a group that notably includes judges.
Nor does emotion count most. When in doubt, people tend to go with how they feel about one side or the other. Who wears the black hat? That packs a bigger wallop than the cold rationality of the parties' competing positions. But feelings get you only so far with your audience.
That leaves the biggest of the big three — character. You make judgments about the moral traits of people all the time. And the reader of a brief quickly forms a view about the credibility and good faith of the writer. Can I trust what she says? Did he do the hard work necessary to give me a true understanding of the facts and the law? Does she have sound judgment? Does he seem wise? Has she tried to help me find the right outcome?
Back to the briefs
The importance of ethos to your ability to persuade means that writing with an earnest desire to convince the court with your high moral character will produce more effective briefs. Precision and snappiness will earn you a halo effect, using only the space you need and no more will project confidence, and simplifying without oversimplifying will stimulate gratitude. All three enhance the judges' opinion of your worthiness and therefore foster belief in the rightness of your logic and emotion.