Q: i am a highschool student who is trying to better understand the McClesky v. Kemp case that i was given by my tea

A: In order to impose death as a penalty, juries are typically called upon to consider aggravating factors--things that made the crime worse--and mitigating factors--things that made it better--as compared to similar offenses. These come in two basic varieties: (1) facts from the offense itself, and (2) facts about the offender. So, for example, mental health problems are often presented as mitigating factors because they help explain why the offender broke the law while not excusing it entirely. Similarly, things such as who the victim is may be considered as aggravating factors. It is worse to harm a child than to harm an adult.

In McClesky, the jury found the murder was of the bad variety because it was committed during the commission of another violent offense, robbery, and because the individual killed was a police officer just doing his job. He apparently offered no mitigating circumstances. Most state's laws around the death penalty spell out things the jury has to be convinced are true before it can recommend a death sentence. Trying to protect police officers by specifically making killing an officer on duty a death penalty eligible offense is common scheme within the law.

As for serial killers, most are charged with death penalty eligible offenses. However, they are often able to make deals to avoid the death penalty because of the nature of their offenses. First, they are considered mentally ill. Second, they often hold the keys to solving unsolved murders and recovering remains for victims' families to bury. Prosecutor often trade in the death penalty in order to bring closure to cases. This is how most serial killer deals work. They don't go to trial, so a jury never decides whether or not to give them the death penalty. Instead, the plead guilty and provide information in exchange for avoiding the death penalty.