WHEN Asif Zardari was about to marry Benazir Bhutto after her return from London in 1986, they had a pact: that he would never venture into politics. Ten years later, he has not just earned a reputation of being the most powerful person in Benazir's two tenures as prime minister, he is even accused of running a parallel government. In the event, he has become her most trusted ally and troubleshooter. Now he is turning into her biggest liability.