The author never attacks the motives of the proponents of jury nullification. He just undermines their position by pointing out negative consequences of the doctrine.

The author doesn’t point out any inconsistencies in the proponents’ reasoning. He just points out the consequences of their position.

The proponents’ premise is that jury nullification is legitimate “because it helps shield against injustice.” The author never argues that this is false, and we can’t presume that his argument implies that it’s false. Instead, he highlights negative consequences of the doctrine.

The author never presents a counterexample to the proponents’ claim. He just presents consequences of jury nullification.

The author undermines the proponents’ conclusion by arguing that the application of the doctrine has undesirable consequences— overreliance on jurors’ objectivity and a tendency for juries to make serious mistakes based on perceived unfairness.