Pakistan became a republic on March 23, 1956, with Maj. Gen. Iskander Mirza as the first president. Military rule prevailed for the next two decades. Tensions between East and West Pakistan existed from the outset. Separated by more than a thousand miles, the two regions shared few cultural and social traditions other than religion. To the growing resentment of East Pakistan, West Pakistan monopolized the country's political and economic power. In 1970, East Pakistan's Awami League, led by the Bengali leader Sheik Mujibur Rahman, secured a majority of the seats in the national assembly. President Yahya Khan postponed the opening of the national assembly to skirt East Pakistan's demand for greater autonomy, provoking civil war. The independent state of Bangladesh, or Bengali nation, was proclaimed on March 26, 1971. Indian troops entered the war in its last weeks, fighting on the side of the new state. Pakistan was defeated on Dec. 16, 1971, and President Yahya Khan stepped down. Zulfikar Ali Bhutto took over Pakistan and accepted Bangladesh as an independent entity. In 1976, formal relations between India and Pakistan resumed.
Pakistan's first elections under civilian rule took place in March 1977, and the overwhelming victory of Bhutto's Pakistan People's Party (PPP) was denounced as fraudulent. A rising tide of violent protest and political deadlock led to a military takeover on July 5 by Gen. Mohammed Zia ul-Haq. Bhutto was tried and convicted for the 1974 murder of a political opponent, and despite worldwide protests he was executed on April 4, 1979, touching off riots by his supporters. Zia declared himself president on Sept. 16, 1978, and ruled by martial law until Dec. 30, 1985, when a measure of representative government was restored. On Aug. 19, 1988, Zia was killed in a midair explosion of a Pakistani Air Force plane. Elections at the end of 1988 brought longtime Zia opponent Benazir Bhutto, daughter of Zulfikar Bhutto, into office as prime minister.