What constitutes an affirmative defense in legal terms?

An affirmative defense is a legal concept where the defendant acknowledges the basic facts of the prosecution's case but introduces new evidence or arguments to justify or excuse their behavior, potentially leading to a not guilty verdict or a lesser charge. This type of defense shifts the burden of proof to the defendant, who must provide evidence to support their claim.

In this context, presenting new evidence is essential because it allows the defendant to offer circumstances that may mitigate their liability or absolve them of guilt. For instance, a defendant might argue self-defense, claiming that their actions, while technically unlawful, were justified under the specific circumstances of the situation. By presenting this new evidence, the defendant seeks to persuade the court that they should not be held liable for their actions based on the justifications provided.

Other choices do not accurately reflect the nature of an affirmative defense. For example, relying solely on the prosecution's evidence or involving no new evidence fails to address the proactive nature required in an affirmative defense. Additionally, a plea bargain pertains to negotiating a deal with the prosecution to plead guilty to a lesser charge, which is distinct from presenting an affirmative defense in court.