Due process mandates that the prosecution prove beyond a reasonable doubt all elements constituting a crime. Affirmative defenses typically don’t negate an element of the crime but introduce extenuating circumstances that could justify or excuse it. This distinction allows jurisdictions to place the burden on defendants for just their defense without infringing on due process protections.
For example: Consider a theft case where duress is claimed—the prosecution must still prove theft occurred, but the defendant must demonstrate they were compelled by threat of harm, thereby not affecting due process adherence.