What got me thinking about this again was this article about a man who was just indicted by a grand jury in what sounds like rather questionable circumstances. The police raided his home. He apparently fired his gun in self-defense before he knew it was the police (or rather, that's his version, which as far as I can see has considerably more credibility than the police version). If the grand jury system worked as it is supposed to, all of the problems with the police case would have been aired in the grand jury and this guy would likely not have been indicted. Grand juries are supposed to prevent prosecutorial misconduct in charging people where those charges are not supported. Instead, it seems like they are just a speed bump on the way to an indictment, no matter what the actual evidence.
It would be great if grand juries worked as intended and prevented questionable prosecutions. That would be a great way to provide a check on the huge, almost completely unchecked power prosecutors have. Though it will probably never happen. I've heard it said (By Posner, no less) that our justice system is designed to make it really easy to convict people without even giving most of them trials because otherwise, it could not function. He says this approvoingly, by the way. (Posner is a 7th Circuit Federal Appellate Judge). Given that only about 3% of cases go to trial, he is probably right that our system would be overwhelmed if every defendant demanded his constitutional right to a jury trial. But that is no reason to deny justice. Posner sees it as not a problem because he thinks most of them are guilty anyway, so the whole due process thing is more of a formality. I think that sort of thinking is dangerous thinking - it is all well and good when it is someone else who is on trial - I wonder if Posner would feel that way if it was him or a loved one accused. I somehow doubt he ever thinks about it that way.
There are lots of ways to deal with prosecutorial misconduct and to potentially check prosecutorial power. This way interests me mostly because it is a mechanism that is already in place (though currently toothless and ineffective). That makes it a good starting point for reform, even if the odds are long.
(1) - It has previously been said that a prosecutor could get a grand jury to indict a ham sandwich. Which is not much of an exageration.