HARARE, Zimbabwe (AP) — President Robert Mugabe swore in his longtime rival as prime minister Wednesday, cracking his nearly three-decade stranglehold on power and conceding they must work together to rescue Zimbabwe from economic and humanitarian disaster. The image of Mugabe administering the oath of office to Morgan Tsvangirai was extraordinary given the history of state-sponsored violence against opponents. The opposition leader has been beaten and was once nearly thrown from a 10th floor window by suspected government thugs.