Zanu-PF Politburo member Cde Perrance Shiri believes that the party could have erred in giving former president Robert Mugabe carte blanche to stay in office for as long as he pleased, as this seems to have made him vulnerable, especially when he became old, to the political designs of a faction led by ex-First Lady Grace Mugabe, which wanted to take over the levers of power in the party and Government.