This claim popped up in a [discussion on Hacker News](http://news.ycombinator.com/item?id=2347885) where it was claimed that if a legal system has a jury it's more likely it will be just. As one commenter put it:

> 
> [..] jury is not as easily bought, harder
>  to threaten, and better at ironing out
>  the moral ambiguities that can be the
>  failings of a single person.
> 
> 
> 

Has there been any evaluations in different legal systems to support or refute that claim?