Opinion on an Ultimate Issue

(a) IN GENERAL—NOT AUTOMATICALLY OBJECTIONABLE. An opin- ion is not objectionable just because it embraces an ultimate issue. (b) EXCEPTION. In a criminal case, an expert witness must not state an opinion about whether the defendant did or did not have a mental state or condition that constitutes an element of the crime charged or of a defense. Those matters are for the trier of fact alone. (As amended Pub. L. 98–473, title II, § 406, Oct. 12, 1984, 98 Stat. 2067; Apr. 26, 2011, eff. Dec. 1, 2011.)