HARARE — Zanu PF maintains that only the Constitutional Court can declare the appointment of General Phillip Valerio Sibanda to the Zanu PF politburo unconstitutional, rejecting growing criticism of President Emmerson Mnangagwa’s surprise decision. Sibanda, the commander of the Zimbabwe Defence Forces, was named an ex officio member of the politburo on October 28 during the annual Zanu PF annual…