When must a criminal trial go before jury?

A criminal trial must go before a jury when the defendant faces serious charges that could result in imprisonment for six months or more, as guaranteed by the Sixth Amendment of the U.S. Constitution. Additionally, if the defendant requests a jury trial and it is granted by the court, a jury will be empaneled to hear the case. In some jurisdictions, there are exceptions for lesser offenses where a bench trial (trial by judge) may suffice.