Pakistan came into being through a constitutionally governed election when Muslims in British India voted for an independent state that comprised the Muslim-majority parts of India. It had two wings: East Pakistan (currently Bangladesh) and West Pakistan, geographically separated by more than a thousand kilometers. Since Islam was the only common link between the two wings, it played a significant role in drafting the first Constitution which was adopted in 1956 and lasted less than two years. For the past seventy-three years, Pakistan has been experimenting with a variety of constitutional models. Interestingly, Islam has had a pivotal role in all of these models. These constitutional models have accommodated a variety of systems of governments in different periods such as a federal parliamentary system (1947-58), a presidential system (1962-69), a parliamentary system (1971-77), a parliamentary system with the army chief as the president (1978-88), a parliamentary system with a strong civilian president (1989-98), a return to a parliamentary system with the army chief as the president (2000-06), and a decentralized federal parliamentary system (2010-present).
Although Islam has consistently maintained a significant role in the constitutional system of Pakistan, various state institutions have taken turns in dominating the state. During the first ten years (1947-1958), the bureaucracy dominated politics. It was the bureaucrat Governor General, Ghulam Muhammad, who manipulated politicians and dissolved the first legislative assembly in 1954. Subsequently, Iskandar Mirza, formerly a civil servant, served as the Governor General and then became the President of Pakistan after the adoption of the 1956 Constitution. Mirza conspired to impose the first Martial Law in October 1958 at the behest of Ayub Khan, then Army Chief. For the next eleven years, Ayub Khan ruled as President. Although he supported “Islamic modernism” as a political slogan, his 1962 Constitution unsuccessfully tried to minimize the role of Islam in the legal system. During the late 1960s, the charismatic feudal lord-turned-politician, Zulfikar Ali Bhutto, mobilized masses under the slogan of “Islamic socialism.” After the secession of East Pakistan in 1971, he established the supremacy of the legislature over the bureaucracy and the military. General Zia ul-Haq toppled Bhutto’s government in a military coup in July 1977 and legitimized his military rule through the promise to establish a Prophetic Order (Nizām e Muṣtafā). Zia ul-Haq’s Islamist sloganeering attracted not only the Islamist parties such as Mawdudi’s Jamat e Islami, but the feudalist and capitalist classes who were adversely affected by the nationalization and land reform policies of Z.A. Bhutto. Bolstered by the US support against the Soviet Union during the Afghan war, Zia ul-Haq introduced crucial constitutional changes by establishing the Federal Shariat Court (FSC) with the mandate to examine state laws for their conformity with the injunctions of Islam. Although Zia ul-Haq’s regime came to a sudden end with his death in August 1988, his institutional structure for the Islamization of laws has survived successive civil and military regimes over the past three decades.
In the post-Zia ul-Haq era, Pakistan’s judiciary started to assert itself and relied upon the entrenched constitutional role of Islam to strengthen its position vis-à-vis other state institutions. During the 1990s, the FSC and the Shariat Appellate Bench of the Supreme Court declared a number of laws repugnant to the injunctions of Islam. Such laws included financial laws which allowed interest (ribā), criminal laws related to homicide and bodily injury (qiṣāṣ and diyat), blasphemy laws, land reform laws, and land acquisition laws. The hallmark of this period is the judgment in which the FSC declared various provisions of the Enforcement of the Shariah Act 1991 as repugnant to the injunctions of Islam. While this Act declared sharīʿa as the “supreme law of Pakistan,” it provided that the validity of the “present political system” shall not be challenged before any court and interest (ribā) would be allowed “till an alternative economic system is evolved.” The FSC struck down the Act by declaring it unconstitutional and un-Islamic because it curtailed the process of Islamization of laws by limiting the jurisdiction of the FSC. The government filed an appeal against this judgment before the Shariat Appellate Bench of the Supreme Court which remains pending to this day. The judicial activism of the FSC came to an end with another military coup in October 1999. The army chief, General Parvez Musharraf, removed a number of judges and legitimized his coup through the Supreme Court judgment by employing the notorious doctrine of state necessity which had legitimized previous military coups in Pakistan’s checkered constitutional history. In the aftermath of September 11, 2001, General Musharraf won US support during the “war on terror.” His dictatorship received an unlikely challenge from the Chief Justice Iftikhar Chaudhry whom he attempted to depose in 2007. After his restoration to the position of Chief Justice, Chaudhry initiated the suo motu regime by effectively trying to run the government from his court room until his retirement in 2013.
During this turbulent constitutional history, the role of Islam has persisted in the constitutional order of Pakistan. The endurance of Islamic constitutionalism and its continued popularity amongst the masses in Pakistan has depended upon the generality and flexibility of the principles of God’s sovereignty (ḥākimiyya), consultation (shūrā), consent (bayʿa), and public interest (maṣlaḥa). These principles have allowed state institutions to align such diverse groups as the military, feudalists, capitalists, ‘ulamā’ (modernist, conservative, and reformists), urban middle-class professionals, civil society, and foreign powers to dominate state power in changing circumstances. Similarly, the range of political sloganeering involving appeals to Islam has also been diverse and has included: Islamic nationalism (1947-58), Islamic modernism (1958-69), Islamic socialism (1970-77), Islamic jihād (1977-88), Islamic democracy (1988-99), Islamic “enlightened moderation” (1999-2008), Islamic juristocracy (2008-18), and Islamic mysticism/spiritualism (2018-present).
The FSC is one remarkable feature of the constitutional system in Pakistan that is vested with the authority to examine any law, with certain exceptions, for its conformity with the injunctions of Islam. During the past forty years, the FSC has evaluated a wide variety of laws and has declared many repugnant. In doing so, the FSC has introduced significant changes in the legal system of Pakistan. A number of these changes relate to due process: the FSC declared the laws related to the armed forces, civil service regulations, and public administration as repugnant to the injunctions of Islam because they did not provide the right to a hearing, fair trial, and appeal. An important feature of the judgments of the FSC has been its endorsement of fundamental rights on the basis of Islamic legal principles. The FSC upheld the right to non-discrimination and gender equality by declaring the provisions of the Citizenship Act 1951 as repugnant for denying the husband of a Pakistani woman the right to citizenship of Pakistan. The FSC also rejected petitions which challenged the appointment of female judges, and endorsed the principle of general equality as enshrined in verse 2:228 of the Qur’ān.
The constitutional history of Pakistan reflects the flexibility of Islam in accommodating a wide variety of governmental systems that are at ease with both liberal and illiberal values. The democratic, dictatorial, and hybrid democratic-dictatorial regimes have relied upon Islamic values to claim legitimacy and public support. In reality, Islamic constitutionalism has played a minimal role in ensuring a representative and accountable government, though Islamic legal principles have justified putting limits on the state authority to protect the rights of citizens.
 Dr. Mehmood ur-Rahman Faisal v. Government of Pakistan, PLD 1992 FSC 1. In 2000, the Shariat Appellate Bench of the Supreme Court confirmed the judgment of the FSC. Muhammad Aslam Khaki v. Syed Muhammad Hashim, PLD 2000 SC 225. However, the government filed a review petition and a reconstituted bench of judges of the Supreme Court returned the case to the FSC for fresh adjudication. The FSC has not yet decided the case.
 Federation of Pakistan v. Gul Hassan Khan, PLD 1989 SC 633.
 The FSC held that the alternative to death punishment in the form of life imprisonment is repugnant. The FSC tried to soften the strictness of the law by clarifying that blasphemy is not a wrong of strict liability, in which neither wrongful intent (mens rea) nor culpable negligence is required for liability. Muhammad Ismail Qureshi v. Pakistan, PLD 1991 FSC 10.
 Qazalbash Waqf v. Chief Land Commissioner, PLD 1990 SC 99; Sajwara v. Federal Government of Pakistan, PLD 1989 FSC 80.
 Amin Jan Naeem v. Federation of Pakistan, PLD 1992 FSC 252.
 Muhammad Ismail Qureshi v. Federal Government of Pakistan, PLD 1992 FSC 445.
 Sections 3, 18 and 19 of the Enforcement of the Shariah Act 1991.
 Zafar Ali Shah v. Pervez Musharraf, Chief Executive, PLD 2000 SC 869.
 The FSC held that equality before the law and equal protection of the law are inherent principles of Islamic law and policy. Therefore, the law which allowed the government to dismiss civil servants before the age of retirement without giving a show cause notice is invalid. Muhammad Ramzan Qureshi v. Federal Government, PLD 1986 FSC 200. The FSC held that certain provisions of the Pakistan Army Act (section 133), the Pakistan Air Force Act 1953 (section 162) and the Pakistan Navy Ordinance 1961 (section 138) are repugnant to the injunctions of Islam because they barred the right of appeal. Pakistan through Secretary Defense v. Public at Large, PLD 1985 FSC 365. The FSC declared that it is against the injunctions of Islam to deny an opportunity for hearing before cancelling, impounding or confiscating one’s passport. Re: Passports Act 1975, PLD 1989 FSC 39.
 In Re: Suo Motu Case No.1/K of 2006 (Gender Equality), PLD 2008 FSC 1.
 Mian Hammad Murtaza v. Federation of Pakistan, PLD 2011 FSC 117; Ansar Burney v. Federation of Pakistan, PLD 1983 FSC 73. The judges specifically referred to the part of the verse which reads, “And women shall have rights similar to the rights against them, according to what is equitable.” The full translation of the verse 2:228 is as follows: “Divorced women shall wait concerning themselves for three monthly periods. Nor is it lawful for them to hide what Allah Hath created in their wombs, if they have faith in Allah and the Last Day. And their husbands have the better right to take them back in that period, if they wish for reconciliation. And women shall have rights similar to the rights against them, according to what is equitable; but men have a degree (of advantage) over them. And Allah is Exalted in Power, Wise.” Not all judgments of the FSC, however, have been pro-women. In 2016, the FSC refused to declare a colonial law as un-Islamic that allowed husbands to get a decree of restitution of conjugal rights against their wives. Nadeem Siddiqui v. Islamic Republic of Pakistan, PLD 2016 FSC 1.