“Mens rea” is the legal term that refers to the mental status, or “guilty mind,” of the defendant at the time the crime was committed. It’s what ultimately helps determine exactly what crime a person should be convicted of having committed, if at all.

For example, murder cases may hinge on whether or not the defendant acted with the intent to kill and whether that intent was planned or unplanned. The difference between a first-degree murder conviction and a second-degree murder conviction, for example, often comes down to the defendant’s mens rea. He or she may have intentionally caused the victim’s death, but was the murder premeditated or a purely impulsive action? If it was premeditated, or planned, it was first-degree murder.

Unintentional behavior, on the other hand, may lack the necessary mens rea to even be a crime.

For example, if you got confused and turned the wrong way on a road at night, driving into traffic, any resulting deaths or injuries are likely to be considered the result of tragic negligence — not criminal intent. On the other hand, if you were drunk when you did it, the fact that you intentionally got behind the wheel while intoxicated is enough to establish your entire actions as intentional — and result in serious criminal charges.

Sometimes, even serious crimes can fail to result in a conviction if the defendant was incapable of the necessary mens rea. Mentally challenged individuals, for example, may lack the intellectual capacity to knowingly participate in drug trafficking but could still be used as unwitting drug mules, delivering packages of drugs for dealers.

It helps to understand why the concept of mens rea is so important to our legal system because the prosecution may explore your motives in order to try to establish the necessary state of mind to convict you of a higher charge — while your criminal defense attorney is equally likely to explore the possibility of a reduced charge or an acquittal based on your state of mind at the time the crime was committed.

Source: Findlaw, “Mens Rea – A Defendant’s Mental State,” accessed March 29, 2017