I think it has good and bad elements, with the good outweighing the bad but requiring reform. I’m from the US but I’m not a lawyer/judge/social worker/academic/journalist/plaintiff/defendant/cop/criminal. Here are my random opinions supporting that.

The good elements that I can think of are:
1. It sometimes reduces the expense of trials.
2. It formalizes a negotiation process that might otherwise happen “under the table.”
3. Because the choice of plea is given to the defendant, it sometimes tips the scales a little bit in favor of the defendant, which I think is good because our system is so punitive.

The bad elements that i can think of are:
1. Because it reduces the expense of trials, it arguably leads to more prosecutions, which I think is bad because our system is so punitive and also because it costs more.
2. It encourages prosecutors to “overcharge” in order to push defendants into pleas which may be overly harsh or not reflect what the defendant actually did.
3. Because the prosecutor usually knows more than the defendant, it can tip the scales in favor of the prosecutor, which i think is bad because our system is so punitive.
4. Because the prosecutor usually has more resources than the defendant, innocent defendants often plead guilty because they can’t afford a trial.
5. Plea bargaining reduces the risk to prosecutors, since it reduces “extreme” outcomes. This encourages more prosecutions, which again I think is bad.
6. Plea bargaining deprives the public and researchers of the information that we would get from trials.
7. Kind of the same as #6: Plea bargaining kind of creates a “prisoner’s dilemma” among defendants. Without plea bargaining, the chance that a few defendants might get off can serve as a deterrent against overly aggressive prosecution. But with plea bargaining, no defendant wants to be the one who steps up to defend themselves, because they would rather take the “safe option” and plead guilty to a lower charge. So the defendants may all end up worse off because nobody wants to “take the hit” of pleading innocent.
8. As plea bargaining becomes normalized, the demand for public defenders goes down so that the option of going to trial may not be realistic, and that reduces the bargaining power of defendants in a plea deal.

You worded it as if it’s an option for anyone to plea down any charge, which is not the case.

My opinion on whether plea bargaining is good or not depends on the specifics of each case, and can be an important and useful tool to enable prosecutions of more important cases.

It is a tool to pressure people into admitting to a crime they did not commit, to avoid the time, expenses, and stress caused by a trial.

^ This. Combined with pretrial detention and the horror of cash bail, innocent people are often persuaded to admit to crimes they didn’t commit. Add a pandemic to the mix, and plea bargains become an even more powerful tool for prosecutors.

It’s an important part of US mass incarceration. Over 97% of federal and 94% of state convictions are obtained through plea bargains.

@capet Wrote a much better answer than I would have. I’m basically in complete agreement with the above pros/cons.

If we had to undergo a full jury trial for every criminal prosecution, we would either need to raise taxes a ton to cover the massive increase in costs and be prepared to serve as jurors much more frequently (perhaps several times per year). This might pressure prosecutors to avoid prosecuting cases that aren’t “slam dunks” which could be both good and bad. It is my understanding that some types of sexual offenses aren’t prosecuted as often as other crimes (but that could be inaccurate)—and these cases might be prosecuted even less often in a world where the courts are jam-packed and backlogged. Also there’s the factor that innocent people could spend very long periods of time in jail if they can’t afford bail while they’re waiting for their trial date.

If I could snap my fingers and make things how I thought they should be, I honestly don’t know which choice I would go with. Maybe plea bargaining wouldn’t be allowed for violent crime or property crime in excess of $1M or something like that?

The concern #2 that @capet raises reminds me of the tragedy of Aaron Swartz where one of the smartest minds of our time committed suicide because he was facing 13 felonies (over 50 years in jail) for publishing copyrighted academic journal articles.