Sometimes a defendant will ask the judge to instruct the jury on a "lesser charge." This gives the jury an opportunity to find the defendant guilty, but of a less serious crime than originally charged. A lesser included charge means that there is an offense similar to the one the defendant is actually charged with that has different elements of proof. For a defendant to be entitled to an instruction on a lesser included offense, there must be some basis on which the jury could find the crime to be less than what the prosecution actually charged. The instruction should be given if the evidence provides a rational basis for a finding of guilt on the lesser offense and an acquittal of the greater. In determining whether to issue the instruction, the court must view the evidence in the light most favorable to the defendant. Such an instruction is often proper when there is some ambiguity in the prosecution's evidence or witnesses (either deduced from direct testimony or cross-examination). However, the defendant is not entitled to an instruction on a lesser-included offense where the prosecution offers uncontroverted evidence on an essential element of the crime.
Some examples of "lesser included offenses" include manslaughter instead of murder, theft instead of burglary, and indecent assault instead of rape.
In the United States, courts are required to give a lesser included offense instruction (if applicable) in a capital case. It is unconstitutional for a statute to prohibit such an instruction in a capital case, because the absence of the lesser included offense instruction increases the risk that a jury will convict the defendant simply to avoid setting him free.