a) Bench Trials By Lone Judges
In U.S. law, for most criminal cases, trial by jury is usually a matter of course as it is a constitutional right under the Sixth Amendment and cannot be waived without certain requirements. Under section 21 of the rules of Federal Criminal Procedure, if a defendant is entitled to a jury trial, the trial must be by jury unless (1) the defendant waives a jury trial in writing; (2) the government consents, and (3) the court approves.
With bench trials, the judge plays the role of the jury as finder of fact in addition to making conclusions of law. In some bench trials, both sides have already stipulated to all the facts in the case (such as civil disobedience cases designed to test the constitutionality of a law). These cases are usually faster than jury trials because of the fewer formalities required. For example, there is no jury selection phase and no need for sequestration and jury instructions.
A bench trial has some distinctive characteristics, but it is basically the same as a jury trial without the jury. For example, the rules of evidence and methods of objection are the same in a bench trial as in a jury trial. B