§ 639 Bias of officer, challenge for.

If jurors are picked by an officer instead of being randomly drawn, and that officer is biased in some way, the whole group of jurors can be challenged because of it. The idea is simple: if the person choosing the jury pool has a reason to favor one side, that unfairness can affect everyone they picked.

This kind of challenge works the same way as challenging a single juror for bias. The person raising the objection has to follow the same steps and rules that apply when questioning whether one juror can be fair. The court then decides the challenge the same way it would decide a challenge against an individual juror.

In short, this rule protects the fairness of the jury selection process itself. It makes sure that if the officer picking jurors has a personal bias, the defense or prosecution has a way to challenge the entire panel, not just individual jurors.