Pakistan came into being as a self-governing dominion in the British Commonwealth in 1947 and declared itself a republic in 1956. Under a constitution framed by Zulfikar Bhutto and effective as of 14 August 1973, it is federal in nature, and Westminster-style cabinet systems operate at the federal and provincial levels. All powers not otherwise specified are reserved for the federal government, which is armed also with extensive emergency powers in the event of a breakdown in constitutional government.
Pakistan is governed under the constitution of 14 August 1973 (as amended) which declared Islam the state religion and provided for a president as a nominal head of state and a prime minister as executive head of government. The president and prime minister were chosen by members of parliament, and the prime minister was responsible to that body, which was elected under universal suffrage at 18 years of age (the voting age was subsequently raised to 21, but then lowered once again to 18 in the October 2002 elections). In 1973, the parliament consisted of a national assembly of 200 elected members plus 10 seats reserved (until 1982) for women and 6 for tribal areas, these reserved seats filled by vote of the elected members. A senate of 63 members included 14 legislators from each of the four provincial legislatures, plus 5 seats reserved for tribal areas and 2 for the federal capital area.
This constitution was suspended in part by the martial law administration that seized power in 1977; army chief General Zia-ul Haq retained his military position while exercising executive powers as chief martial law administrator (CMLA). He took on the position of president in 1978 when the incumbent stepped down, In an interim document of 24 March 1981, Zia revived much of the 1973 constitution, although its Fundamental Principles and its electoral provisions remained suspended until martial law was lifted in 1985. The CMLA was initially assisted by an appointive council of advisors, then by an advisory Federal Council of 277 appointed members that was formed in 1982 to assist and advise the martial law government.
The 1973 constitution was fully restored with the lifting of martial law in December 1985, although amended in a number of ways. It redressed— in favor of the presidency—the balance of powers between the positions of prime minister and president, who also remained commander-in-chief of the armed forces. It established term limits of five years for the incumbents, and provided that their successors in 1990 would be elected, the president by an electoral college composed of members of the national assembly, the senate, and the provincial assemblies, and the prime minister, by the national assembly.
In May 1994, after what appeared to be an encouraging start, Benazir Bhutto's government again appeared haunted by ineffectiveness when she failed to get her candidate elected president of the senate—effectively vice president. Instead, she was forced to acquiesce in the reelection, one more time, of the PML's Wasim Sajjad.
Bhutto was ousted in 1996 after President Leghari's charges that her government was corrupt, a move that was supported by a 6–1 supreme court ruling. Nawaz Sharif was elected in February 1997 and immediately instituted sweeping changes affecting the government, military, and economy. On 1 April 1997, both houses of the parliament voted unanimously to repeal the eighth constitutional amendment. The measure, introduced by Sharif, curtailed the president's power to dismiss elected governments and placed the appointment of provincial governors and the chiefs of the armed services in the hands of the prime minister. Sharif reduced the influence of the military in government by dissolving the Council for Defence and National Security. The prime minister also announced he was intending to place plans for introducing "Islamic government" to Pakistan before the legislature in March 2000.
President Leghari stepped down from office in December 1997, and Nawaz Sharif's strengthened his hold on the government when his nominee for president, Mohammad Rafiq Tarar, was elected by a record margin on 31 December 1997.
Sharif's government was overthrown on 12 October 1999, in a military coup staged by the army chief, General Pervez Musharraf, who suspended the constitution and assumed the title chief executive. On 20 June 2001, Musharraf appointed himself president. On 30 April 2002, a referendum held on Musharraf's presidency reaffirmed him in office for an additional five years. Musharraf promised to restore democracy, and parliamentary elections were scheduled for 10 October. On 21 August, Musharraf announced 29 amendments to the constitution. A National Security Council was established, with the president as chairperson, and the joint chiefs of staff and three service chiefs as members. It was established as a consultative body, but is to deal with matters pertaining to the "sovereignty, integrity, and security" of the state. Its complete jurisdiction has not been defined. In addition, Musharraf granted new powers to the president, including the right to dissolve the national assembly at his or her discretion, to appoint governors and to dissolve provincial assemblies in consultation with them, and to appoint the joint chiefs of staff and the three service chiefs in consultation with the prime minister. Musharraf indicated the changes would introduce a system of checks and balances between the president, prime minister, and chief of the army staff. He stated the constitutional amendments incorporated by his government were irreversible and needed no validation by the parliament to be formed after the 10 October 2002 elections.
The parliament, or Majlis-i-Shura, has two chambers. As of October 2002, the national assembly had 342 members, elected for five year terms, 272 of whom are elected in single seat constituencies; 10 seats for minorities are filled by the nominees of political parties on the basis of the latter's strength in national assembly elections; and 60 seats for women are nominated by political parties in accordance to their share of national assembly seats per province. The senate has 100 members, elected by the provincial parliaments. Of the 66 general seats, 14 have been allocated to each of the four provinces, while the federally administered tribal areas (FATA) and the federal capital are assigned 8 (directly elected) and 2 seats (according to national assembly elections) respectively. The general seats are open to all, irrespective of gender or religion. In addition, each province has been conferred four seats for technocrats and four for women. Two seats, one for technocrats and another for women, are reserved for the federal capital.
On 10 October 2002, in the first general election since Gen. Musharraf seized power in 1999, Quaid-e-Azam, a political faction of the Muslim League supportive of Musharraf, won 118 of the 342 parliamentary seats. The Pakistan People's Party, aligned with former prime minister Benazir Bhutto, who was banned from participating, took 81 seats, and the religious 6-party coalition Muttahida Majlis-e-Amal (United Action Front or MMA) won 60 seats. The party aligned with former prime minister Nawaz Sharif, the Pakistan Muslim League-Nawaz, won 19 seats. Twelve other party groupings took seats in parliament. Although President Musharraf declared the elections to be free and fair, the European Union declared the elections to be flawed. In November, parliament elected Zafarullah Khan Jamali prime minister, to head a coalition government for three years.