What Is the Burden of Proof in a Criminal Case?
In criminal cases in the United States, defendants (people accused of committing crimes) enjoy the presumption of innocence, which means they are legally considered innocent until a state or federal prosecutor proves their guilt “beyond a reasonable doubt.” This obligation is known as the burden of proof.
This sounds pretty straightforward, but like so many things in the legal field, the burden of proof can get rather tricky. The terms “proof beyond a reasonable doubt,” “clear and convincing evidence” and “preponderance of the evidence” are all standards of proof.
What does standard of proof mean?
It may help to think of standard of proof as a hierarchy. Certain circumstances require a more stringent standard of proof than others. There are three main standards of proof:
- 1. Proof beyond a reasonable doubt
- 2. Clear and convincing evidence
- 3. Preponderance of the evidence
In criminal cases, the defendant is in jeopardy of losing his or her liberty, which is arguably the most fundamental constitutional right American citizens enjoy, at the hands of the government. Because the stakes are so high, the highest standard of proof, proof beyond a reasonable doubt, is required for a conviction. The other two standards of proof are less stringent and used mainly in civil cases.
Proof beyond a reasonable doubt
To establish proof beyond a reasonable doubt in criminal cases, prosecutors must convince juries that the evidence leads only to the defendant’s guilt and no other reasonable conclusion. In all criminal cases, the jury’s verdict of guilt must be unanimous.
Elements of crime
As part of the burden of proof in criminal cases, prosecutors must prove all elements of the crime to secure a conviction. Elements of crime can change a bit from one crime to another. Generally speaking, however, all crimes are made up of three core elements:
- Actus reus
- Mens rea
- Causation
To convict someone of a criminal offense, the prosecution must prove all three of these elements beyond a reasonable doubt. Here’s a quick overview of these elements:
Actus reus
Actus reus refers to the criminal act itself and whether or not it occurred. It can also refer to failing to act when a person has a duty to do so. For example, psychologists have a legal duty to notify authorities when their patients threaten to harm themselves or others. If they fail to do so, that failure would satisfy the actus reus element.
Mens rea
The mens rea element is probably the most difficult element of crime to explain; it refers to the defendant’s mental state and intentions when they committed the alleged offense. To satisfy the mens rea element, prosecutors have to prove that a defendant acted with a guilty mind. For example, consider two people who cheated on their taxes, one who knowingly claimed an exemption to which he or she was not entitled and another who simply made some kind of clerical error.
In this scenario, the person who deliberately cheated would satisfy the mens rea element, but the person who merely miscalculated would not. It’s important to note that ignorance of the law (not knowing a particular act is illegal) does not generally negate culpability.
Causation
To satisfy the element of causation, prosecutors need only prove that a defendant’s actions caused the illegal outcome. For example, if someone is texting and driving, runs a red light and crashes into another motor vehicle, then a prosecutor would only have to prove that the defendant’s negligence caused him or her to run the red light, which resulted in the subsequent crash.
Affirmative defenses
There are rare occasions in criminal cases when the burden of proof shifts temporarily to the defense. This happens most frequently in the case of affirmative defenses. An affirmative defense is a defense in which the defendant offers evidence that would lessen or negate his or her criminal liability. Examples of affirmative defenses include:
- Insanity
- Self defense
- Necessity
- Involuntary intoxication
When presenting evidence that may reduce or negate liability, it’s up to the defense to convince the jury that such circumstances were present.
Some criticize the burden of proof as being too restrictive on prosecutors, but many believe it’s more acceptable to let a guilty person go free than to convict an innocent one.