What level of proof is required for an affirmative defense?

The correct response indicates that the level of proof required for an affirmative defense is "preponderance of the evidence." This standard means that the evidence presented by the defendant must be more convincing than the evidence presented by the prosecution. In practical terms, it requires that the defendant’s evidence shows that there is a greater than 50% likelihood that their claims are true. This lower standard of proof is applicable because an affirmative defense does not dispute the fact of the crime but seeks to establish circumstances under which the defender should not be held criminally liable.

In contrast, "proof beyond a reasonable doubt" is generally the standard used to determine the guilt of a defendant in a criminal trial, which is a significantly higher standard. "Clear and convincing evidence" is yet another standard that sits between the two, often used in civil contexts but not typically applied to criminal matters such as affirmative defenses. Thus, the preponderance of the evidence standard ideally reflects the degree of certainty required to accept an affirmative defense in court.