Juries are obligated to follow the law judges give them. So, whether a jury has the option of convicting a defendant of a lesser included offense—a crime contained within a more serious crime—depends on the instructions the judge gives.
Most of the time, a defendant who rejects a plea and takes the case to trial wants an acquittal. But there are times when defendants know that’s probably not going to happen: The jury is likely to find that the accused committed some kind of crime, even if not exactly what the prosecution charged. In that kind of case, the defendant might think it’s a good idea to ask the judge to instruct the jury on a lesser included offense—that is, to explain to the jury what the lesser included offense is and give it the option of convicting on that basis. That way, the hope is, the defendant can avoid a conviction on a more serious charge. (A defendant might also want an instruction on a lesser related offense.)
On the other hand, the prosecution may also want a lesser-included-offense instruction, because it wants to make sure that the defendant doesn’t skate on all charges.
A common rule is that a judge must instruct a jury regarding any lesser offense that’s necessarily a part of the charged offense if there’s significant evidence that the defendant committed only the lesser crime. State law may provide that neither the prosecution nor the defense has a greater right to demand or oppose instructions on lesser included offenses. In fact, courts have held that even if neither side asks for, and each objects to, a lesser-included-offense instruction, a judge must give it “if there is substantial evidence that the defendant is guilty only of the lesser” offense. (People v. Birks, 19 Cal.4th 108 (1998).)
Generally, a judge has to give a jury instruction on a lesser included offense only if the evidence supports it. For example, simple drug possession is usually a lesser included offense of drug possession with intent to distribute (or sell). In many instances, an instruction on each of these offenses is appropriate. But there can be circumstances where the evidence doesn’t support both. For example, the judge might be free to refuse to give an instruction on simple possession if the defendant was nabbed with “pay/owe” sheets, scales, and mountains of drugs—this evidence suggests the drug possession was in no way for personal use. (See United States v. Lucien, 61 F.3d 366 (5th Cir. 1995).)
Whether one crime is a lesser included offense of another depends on the definitions of the crimes. And some courts use different tests to determine whether a crime is “lesser included.” Courts may have different rules as to when lesser-included-offense (or lesser-related-offense) instructions are appropriate or required. For instance, could a particular defense presented by the defendant block the jury from considering a lesser included offense?
Other factors can complicate matters, too, like whether state law allows the defendant to waive lesser-included-offense instructions. Another potential issue: Does state law ever provide that a defendant can forfeit the right to instructions on lesser included offenses?
In short, the complexity and variety of laws on lesser included offenses are part of why it’s crucial to seek the advice of an attorney before deciding to take a plea deal or go to trial. Laws vary from state to state, and from state to federal court, and a good attorney familiar with the applicable laws will be able to adequately help you.