The president, however, is the head of state, the head of government, and the head of a multi-party system. Nigerian politics takes place within a framework of a federal, presidential, representative democratic republic, in which executive power is exercised by the government. Legislative power is held by the government and the two chambers of the legislature: the House of Representatives and the Senate.
Together, the two chambers make up the law-making body in Nigeria, called the National Assembly, which serves as a check on the executive arm of government. The highest judiciary arm of government in Nigeria is the Supreme Court of Nigeria. Nigeria also practices Baron de Montesquieu's theory of the separation of powers based off the United States system.
The law of Nigeria is based on the rule of law, the independence of the judiciary, and British common law (due to the long history of British colonial influence). The common law in the legal system is similar to common-law systems used in England and Wales and other Commonwealth countries. The constitutional framework for the legal system is provided by the Constitution of Nigeria.
English Law, which is derived from its colonial past with Britain;
Common law, (case law development since colonial independence);
Customary law, which is derived from indigenous traditional norms and practices;
Sharia law, used in the northern part of the country.
Like the United States, there is a judicial branch, with the Supreme Court regarded as the highest court of the land.
The president is elected through universal suffrage. He or she is both the chief of state and head of government, heading the Federal Executive Council, or cabinet.
The executive branch is divided into Federal Ministries, each headed by a minister appointed by the president. The president must include at least one member from each of the 36 states in his cabinet.
The President's appointments are confirmed by the Senate of Nigeria. In some cases, a federal minister is responsible for more than one ministry (for example, Environment and Housing may be combined), or a minister may be assisted by one or more ministers of State. Each ministry also has a Permanent Secretary, who is a senior civil servant.
The ministries are responsible for various parastatals (government-owned corporations), such as universities, the National Broadcasting Commission, and the Nigerian National Petroleum Corporation. However, some parastatals are the responsibility of the Office of the Presidency, such as the Independent National Electoral Commission, the Economic and Financial Crimes Commission and the Federal Civil Service Commission.
The National Assembly of Nigeria has two chambers: the House of Representatives and the Senate. The House of Representatives is presided over by the Speaker of the House of Representatives. It has 360 members, who are elected for four-year terms in single-seat constituencies. The Senate, which has 109 members, is presided over by the President of the Senate. 108 members are elected for four-year terms in 36 three-seat constituencies, which correspond to the country's 36 states. One member is selected in the single-seat constituency of the federal capital.
The judicial branch consists of the Supreme Court of Nigeria, the Court of Appeals, the High Courts, and other trial courts such as the Magistrates', Customary, Sharia and other specialised courts.
The National Judicial Council serves as an independent executive body, insulating the judiciary from the executive arm of government. The Supreme Court is presided over by the Chief Justice of Nigeria and thirteen associate justices, who are appointed by the President of Nigeria on the recommendation of the National Judicial Council. These justices are subject to confirmation by the Senate.