[pluma]

I'd put it a little differently: it's the job of the prosecutor to ensure that public order is upheld. Americans tend to get distracted by the ambiguous notion of "justice" and what is or isn't "just" (even when the two are orthogonal).

Justice is for the courts to decide, not the prosecutor. But whether enforcing a law serves to uphold the public order is up to the prosecutor. And enforcing bullshit laws is just as problematic as being inconsistent in what laws you do enforce.