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The Mens Rea Project


This Project

What is mens rea?

What's the issue?

There are two main parts to every crime: the actus reus (guilty act) and the mens rea (guilty mind). For example, in the case of murder, the actus reus is the act of killing a person, while the mens rea is the murderer's intent to kill. This is why homicide law is a hierarchy with different degrees of severity; lower degrees of homicide require lower levels of culpability.


The four standard mens rea terms outlined in the Model Penal Code are (in descending order): purposely, knowingly, recklessly, and negligently.

Mens rea is legally complex, so we recommend checking out this short LawShelf post to better understand the differences between these terms.

How is mens rea relevent to sexual assault?

Historically, the actus reus requirements for sexual assault convictions have been so problematic that these were the only focus (i.e. requirement of force, allowance of marital rape, requirement that the perpetrator is male and the victim is female). Very few people are aware that, today, burdensome and unnecessary mens rea requirements are a major issue.

According to the Rape, Abuse, & Incest National Network (RAINN), only 0.5 percent of sexual assault cases lead to convictions, which is significantly lower than for comparable crimes. Improving mens rea will certainly increase this number. 

What we have found is that in cases where the victim is incapacitated due to an intoxicating substance (which is the case in 7 out of 10 rapes), mens rea frequently stands in the way of justice. 

Under most state laws, federal law, and many university policies, in order to find a person guilty of sexual assault (in cases where the victim was incapacitated), the following elements must all be proven:

  1. The defendant knowingly engaged in a sexual act with the victim

  2. The victim was incapacitated due to an intoxicating substance or disability, so therefore could not consent

  3. The defendant knew that the victim was incapacitated

This last element is not necessary for sexual assault to have occurred. If a person is incapacitated, they cannot consent. Engaging in a sexual act without consent constitutes sexual assault regardless of the defendant's knowledge of the surrounding circumstances.

Additionally, this last element places an unnecessary and significant burden on the prosecution, leading to fewer sexual assault cases prosecuted, and fewer perpetrators convicted.

How can this be fixed?

Congress, state legislatures, and universities can fix this by simply altering the current wording or including statutory language that clarifies the mens rea requirement concerning the victim's incapacitation. This language varies depending on the statute or policy, so must be looked at on an individual basis. This must be accomplished in each state individually.

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