He was the Chief Justice of Pakistan when the 1999 military coup d'état was staged by then-Chairman of the Joint Chiefs of Staff Committee and Chief of Army Staff General Pervez Musharraf. Notably, he defied the request given by Musharraf via the Law Minister and Legal Adviser Sharifuddin Pirzada to take a new oath under the Provisional Constitutional Order (PCO) saying that: "Taking an oath under the PCO, in my opinion, will be a deviation from the oath I had taken to defend the constitution of 1973". The PCO not only negated the independence of the judiciary and democratic norms, but also prolonged the martial law by nullifying the effect of any judgement given against President Pervez Musharraf's government.