Sardar Sherbaz Khan Mazari entered politics by supporting Fatima Jinnah, sister of Mohammad Ali Jinnah, against Ayub Khan in the Presidential elections of 1964. In 1970, he was elected to the National Assembly as an independent candidate . He was a signatory to the 1973 Constitution, as head of the independent group in the Assembly. After the Bhutto-led army action in Balochistan and the subsequent banning of the National Awami Party, he formed the National Democratic Party. This was part of an effort to oppose Zulfiqar Ali Bhutto's autocratic rule as well as to bring about peace in Balochistan. He served as the leader of the NDP from 1975 to 1985 and the leader of the Opposition in Parliament from 1975-1977. A former friend of Zulfiqar Ali Bhutto, he became one of his main political opponents in the Pakistan National Alliance. The 1977 elections led to a civil agitation movement which ultimately ousted Zulfiqar Ali Bhutto's government and brought in Martial Law under General Zia.