Effecting the Westminster system for governing the state, the government is mainly composed of the executive, legislative, and judicial branches, in which all powers are vested by the Constitution in the Parliament, the Prime Minister and the Supreme Court. The powers and duties of these branches are further defined by acts and amendments of the Parliament, including the creation of executive institutions, departments and courts inferior to the Supreme Court. By constitutional powers, the President promulgates ordinances and passes bills. The President acts as the ceremonial figurehead while the people-elected Prime Minister acts as the chief executive (of the executive branch) and is responsible for running the federal government. There is a bicameral Parliament with the National Assembly as a lower house and the Senate as an upper house. The judicial branch systematically contains an apex Supreme Court, high courts of four provinces, district, anti-terrorism, Sharia, and the green courts; all inferior to the Supreme Court.
The full name of the country is the Islamic Republic of Pakistan. No other name appears in the Constitution, and this is the name that appears on money, in treaties, and in legal cases. The "Pakistan Government" or "Government of Pakistan" are often used in official documents representing the federal government collectively. Also, the terms "Federal" and "National" in government institutions or program names generally indicate affiliation with the federal government. Because the seat of government is in Islamabad, "Islamabad" is commonly used as a metonym for the federal government.
The Federal Government is Subject to the Constitution. The executive authority of the Federation shall be exercised in the name of the President by the Federal Government, consisting of the Prime Minister and the (Federal) Ministers, which shall act through the Prime Minister, who shall be the chief executive of the Federation.
In the performance of his functions under the Constitution, the Prime Minister may act either directly or through the (Federal) Ministers.
The basic civil and criminal laws governing the citizens of Pakistan are set down in major parliamentary legislation (a term inherited from the United Kingdom), such as the Exit Control List, the Pakistan Penal Code, and the Frontier Crimes Regulations. By the Article 246th and Article 247th to the constitution, the Islamic Jirga (or Panchayat) system has become an institution for local governance. The 1950s reforms in the government administration, the constitutional law and jurisprudence in Pakistan have been greatly influenced by the United States Of America ' legal system. Since the 1970s, the traditional jirga-based law has also influenced the country's judicial development.