"[1]: 633 The Durham rule was abandoned in the case United States v. Brawner, 471 F.2d 969 (1972).
[1]: 634 After the 1970s, U.S. jurisdictions have tended to not recognize this argument as it places emphasis on "mental disease or defect" and thus on testimony by psychiatrists and is argued to be somewhat ambiguous.
The problem with the "product test" was that it gave psychiatric and psychological experts too much influence in a decision of insanity and not enough to jurors.
It is the jury's job to decide whether a defendant's actions were the product of his mental disease or defect.
The expert witness' job is to determine whether the defendant possesses a mental disease or defect.