If the grand jury had indicted Darren Wilson, would prosecutors have been obliged to ignore it?

The problem is that, as Georgetown law professor Randy Barnett noted on Twitter in response to my blog post, “Prosecutors have an ethical obligation not to prosecute those they think are innocent.” If McCulloch believed Wilson was innocent, why would he let the grand jurors decide whether charges should be brought? And if they did approve charges, wouldn’t he be ethically obligated to disregard their determination?

“Whatever [your] decision is, it will be the correct decision and we will stand by that 100 percent,” Alizadeh told the grand jurors. “Our opinions don’t matter. It is up to you and what you guys think.” Yet this seems like a situation where only one outcome was acceptable, which renders the whole process suspect.