Judges vs. juries
Over at Volokh Conspiracy there is an interesting debate (I link to the page in general since there are several postings) over a survey, quite large, of federal criminal cases that concludes judges are MUCH more likely to acquit than juries. It also concludes that this gap arose after 1989 -- before then, there was little difference.
The difference appears to span all types of cases -- misdemeanors as well as felonies, defendants represented by PDs and those represented by private counsel, etc.. There is a debate as to why, and the one explanation that seems to hold water is that the stiff sentencing guidelines (which are/were indeed VERY stiff) make judges more willing to hold the prosecution to a strict standard of proof. I'd say this is an argument for a fully informed jury (i.e., where the jury knows the likely punishment). Judges who are "in the know" hold to a stricter standard of proof than juries who are kept in the dark. There is also a risk of self-selection: you only go to a judge on a case with a clear legal defense -- but why would this only arise after 1989?
They note that defendants routinely go for jury trial anyway, and when they ask for a bench trial prosecutors don't use their veto power.