(a) No attorney at law in a criminal case shall argue to or in the presence of the jury that a defendant, if convicted, may not be required to suffer the full penalty imposed by the court or jury because pardon, parole, or clemency of any nature may be granted by the Governor, the State Board of Pardons and Paroles, or other proper authority vested with the right to grant clemency.

(b) If counsel for either side in a criminal case argues to or in the presence of the jury as provided in subsection (a) of this Code section, opposing counsel shall have the right immediately to request the court to declare a mistrial, in which case it shall be mandatory upon the court to declare a mistrial. Failure to declare a mistrial shall constitute reversible error.

(c) This Code section shall be construed as setting forth requirements in addition to other requirements of law.