This is separate from the rule of law in the US where a prosecution must prove its allegations beyond a reasonable doubt. It is true that a defense is not required to make any claims or present any evidence. However, depending on the jurors selected, in order to instill or preserve a reasonable doubt, some claims may need to be made. In order for a juror to believe a claim, that individual juror will need to find or receive some evidence sufficient for them to believe the claim.
Historically this may even have been a unusual, but not that uncommon practice. aka trusting in 'the gods' or some such.
Rumors to the contrary, we do have a right to free speech, so you can say anything you want in a courtroom without being arrested, unless it causes immeidate danger (e.g. yelling "FIRE!").
When jury selection happens, I have heard that you can be rejected from being on the jury if you say (essentially) that you don't agree with the law. Not agreeing with the law is precisely what leads to jury nullification.
"F@$% you, your honor!”
“Bailiff, please arrest mr. nthj for contempt of court”
So, saying you'll be arrested for talking about jury nullification in court doesn't really give an accurate picture. Though it is probably technically true.
I think that they aren't medieval precisely because we have trial by jury, jury nullification, etc.
I would expect trials in non-common-law countries to feel much more medieval.
This is not really the case. It would be tough to find all jurors didn't LIKE the law. The people sitting on the jury were asked questions during the selection process to make sure they are neutral. The question is, do they understand the law and the issues at hand.
The prosecuting team bears the burden of proof (obviously). The prosecutors are required to prove their version of the actual events. This means that the proposition that is being presented before the judge / jury by the prosecution must be proven to the extent that there could be no reasonable doubt that the defendant is guilty. The defense needs to convince the criminal jury so they are unable to find beyond a reasonable doubt, that this guy is guilty.
The defense seems to be casting doubt for the jury to consider from the get-go. Well played.
There are a few benefits as for example Juries are harder to bribe and sequestered juries are harder to tamper with. But, the core issue and why they were considered so important is there a check on unjust laws or even just laws unjustly applied.