I suspect this varies, for whatever reason. I heard of a civil case (this was a judge talking while we were in jury duty, waiting for a civil case to either be negotiated out-of-court at the last minute, or come to trial) where a jury came to an "unexpected" (by prosecutor and defense, as well as the judge) verdict, and months later a juror came forward with the story that another juror had read something from some book such as a real estate manual that led the jury down the "wrong" path. This was considered tampering (or maybe a violation of protocol, as William said) and bad behavior by the other juror. Rather than a judge making a ruling, the case was retried and the "right" verdict was given by the new jury.Yep. There are checks and balances of all different types built in all over the place in the American system.
If a judge believes a jury really decided in error, for a variety of reasons, the judge can overrule the verdict.
An example would be a juror that agrees a defendant was found to be smoking marijuana, but believes that the laws against smoking marijuana are wrong and should not be enforced....
If a jury believes that someone is actually guilty but shouldn't be convicted, they can acquit, which goes against what they're basically sworn to do, but is their right nonetheless. That's jury nullification, if you want to read about it.
In the past, it was feared that a single judge or panel of government officials may be unduly influenced to follow established legal practice, even when that practice had drifted from its origins. In most modern Western legal systems, however, juries are often instructed to serve only as "finders of facts", whose role it is to determine the veracity of the evidence presented, the weight accorded to the evidence,[1] to apply that evidence to the law, and to reach a verdict; but not to decide what the law is. Similarly, juries are routinely cautioned by courts and some attorneys not to allow sympathy for a party or other affected persons to compromise the fair and dispassionate evaluation of evidence during the guilt phase of a trial. These instructions are criticized by advocates of jury nullification. Some commonly cited historical examples of jury nullification involve the refusal of American colonial juries to convict a defendant under English law.[2]
I suspect this varies, for whatever reason. I heard of a civil case (this was a judge talking while we were in jury duty, waiting for a civil case to either be negotiated out-of-court at the last minute, or come to trial) where a jury came to an "unexpected" (by prosecutor and defense, as well as the judge) verdict, and months later a juror came forward with the story that another juror had read something from some book such as a real estate manual that led the jury down the "wrong" path. This was considered tampering (or maybe a violation of protocol, as William said) and bad behavior by the other juror. Rather than a judge making a ruling, the case was retried and the "right" verdict was given by the new jury.
It varies in that it's rare and discretionary, but it doesn't vary in the way you're suggesting, if I understand you correctly.
What you're talking about sounds like a mistrial. That's not a case like I was talking about. Issues like that, jury tampering, witness tampering, big procedural problems can lead a judge to declare a mistrial. The state then has the option to retry or let it go.
What I was talking about when I said the judge believes the jury has made a mistake would be kind of the opposite of jury nullification. For instance, say there was someone on trial for an assault, and the assault was on tape so the time was known but the person's face wasn't visible. If the defendant was shown by the defense to be at work, at a retail job, during the assault, and/or too tall or short to have been the assailant, but the prosecutor says it's possible records were fudged and the manager of the store lied and he was wearing lifts, and he has a criminal past, convicted of assaults (and this was brought up in an appropriate manner), and the jury convicted him anyway, the judge could feel the jury was simply too obviously wrong to let it go.
If, for instance, the judge felt they had not followed instructions (not in a tampering way, but in a 'beyond reasonable doubt/this case alone/finders of fact/no prejudging way'), he or she could reverse the verdict and acquit the defendant. The judge could do this because he or she felt the facts very clearly supported an acquittal and the jury didn't do what they should have because they prejudged him based on looks and his prior crimes.
I was willing to "do my duty" but with that experience and all the other stuff I heard (that judge liked to stand up and talk, but then we were just waiting, and there wasn't much else to do), I was glad that the case we were going to hear came to an out-of-court settlement (thus my total jury duty experience lasted from 9AM to noon). The US legal/"justice" system is a very complicated and convoluted thing, and I expect it's similar in most other countries.
And then you wrote some more in your post:
An example would be a juror that agrees a defendant was found to be smoking marijuana, but believes that the laws against smoking marijuana are wrong and should not be enforced.
But it's one of the most cantankerous things I've heard about (as your statement that I bolded suggests). My understanding is that NO ONE working in the Justice System (prosecutors, defense attorneys, judges) wants anyone who knows anything about, or that has even heard of jury nullification to be on a jury. Wikipedia explains this:
Yep. There are checks and balances of all different types built in all over the place in the American system.