Well I didn't downvote you, but: "Desirable behaviour" would be for a prosecutor to seek truth, not conviction. That's what I would call "normal". And guess what: there are countries in this world where prosecutors think like that: they are glad to drop charges as soon as they see someone's innocent.

That's exactly what I've written.

Unless you want to assume that the court is so broken, it will willy-nilly convict innocents.

But then it doesn't matter much what the prosecutor does, then the justice system is utterly broken.

You don't have to assume; paying attention would suffice.

Racial disparities, emphasis on victimless crime, asset forfeiture, prison overcrowding, and oh, the fact that USA has a much higher incarceration rate than any comparable polity ever in the history of the human race.

A justice system is broken when people break the rules and subvert the intent of the system. But most of what you're pointing to is, instead, conscious policy choices.

E.g. a society is generally entitled to criminalize activities it does not want people to engage in. That some other people may perceive the crimes as "victimless" is neither here nor there. I'd imagine that very few people convicted of drug crimes are not in fact guilty of those crimes, because the evidence in those cases is usually overwhelming (e.g. caught with physical product in hand).

Similarly, the U.S. has had about 5-10x the murder rate of, say, the U.K., going back probably a century or more, long before the recent rise in incarceration rate. So the fact that the U.S. has a high incarceration rate does not by itself mean that innocent people are being put in prison.

Very little about American policy is "conscious" at the level of us simple citizens. Ignoring that, this is a neat morsel of sophistry! The hundreds of thousands of people who are imprisoned in USA, who would be free in any other nation anywhere ever, aren't "innocent". And why not? Because we define them to be guilty. Ingenious!

Except criminal justice policy is uniquely conscious at the level of citizens. Judges and prosecutors are elected local officials in most states. Three strikes laws were passed by public referendum in places like California. Polls show 80%+ support in favor of keeping hard drugs illegal.

And anyone is ever guilty only because we define it to be so. In the state of nature, robbing a store and killing the clerk is simply the stronger animal exercising its free will over the weaker. And if robbery is illegal because we say so, I fail to see how the robber is less guilty of the crime because one country punishes him with 3 years in prison while we punish him with 10.

It's not just us who consider robbery and murder to be crimes. Every criminal code in history has done the same (although there are often exceptions carved out, especially for murder in the service of the sovereign), and some have even instituted more severe penalties for these actual crimes than we have.

I don't see "don't smoke or sell pot" anywhere in the Ten Commandments.

The judge/jury/overall process seek the truth. I do not consider that the role of the prosecutor at all. I don't think legal philosophy aligns that way either?

I think it's a bit different in the United States, but in my country (D), for example, prosecutors have detailed guidelines how to proceed.

For one, they are obligated to investigate any exonerating evidence and circumstances, and any exculpatory circumstances. All of this must be revealed fully to the court and the defense, prior to the main trial.

For another, they must only charge when they believe that a conviction is more probable than an acquittal ("my chances are at best 20%, but let's see how it goes" would be clear misconduct).

In practice, the conviction rates are more than 90%, for sure (if you count a conviction for a lesser crime).

As a prosecutor once told me: trials can be freak events. After listening to the witnesses firsthand, or after some dramatic revelation, everything can look much different than it looked in the file. But other than that, they almost always win at least partially.

And another reason is workload. Apart from really high profile, highly publicized cases, resources are extremely limited and prosecutors mostly try to close the files.

This is one of the core debates in legal philosophy: Do you want a adversarial or inquisitorial system? Different countries come down on different sides and most legal systems exists somewhere on the continuum. The US adversarial system is far from universals.

I'm not clear why this comment was downvoted either, except perhaps that you mentioned being downvoted, which is a downvote magnet.

But I think you're right: I think it's desirable that prosecutors let go of most cases in which they're not confident of a win. That's called "prosecutorial discretion". If caseloads are high, we want them working on the clearest-cut violations --- maybe with some public policy stretch cases sprinkled in.

Prosecutors should be focused on justice. They should not evaluate themselves, or be evaluated on, the narrow metric of conviction rates. Sometimes doing their job properly should mean being allowed to change their minds, to admit that maybe they're prosecuting the wrong person, or to conceive that the interests of justice are best served by a lighter or suspended sentence. And this is how it works in most of Europe; magistrates are entirely independent, and not beholden to political pressures or to the court of public opinion.

Every case a prosecutor takes and fails to convict is an instance in which the state inflicted harm on a citizen that was later proven to have been unjustified.

Sometimes that's a risk worth taking, but not often. Acquittals are a bad thing.

Humility is never a bad thing. Better to own up to your mistakes than to keep going out of pride.