The 1963 republican constitution swept away all the vestiges of colonial rule in Nigeria. Nigeria became a federation of four regions each of which had its own constitution. The Queen of England ceased to be in control of the arms of government in Nigeria.
The 1963 republican constitution contains most of the provisions of the 1960 independence constitution and new provisions. The Head of State became the President and Commander in Chief of Nigeria Armed Forces. The President appointed the person who appeared to command majority support in the two Houses of Legislature as the Prime Minister.
On the prime minister advice he appointed other ministers. The national legislature was made up of the House of Senate and House of Representatives. The House of Senate was made up of 56 Senators including the Senate President. The House of Representatives was made up of 312 members elected from single member constituencies.
Citizens of Nigeria that had attained the age of twenty-one were elected into the House of Representatives. The House of Representatives elected a speaker from among themselves to co-ordinate the activities of the house. The national legislature has the main function of deliberating on important matters affecting the nation and making resolutions which are passed in the form of bills.
The executive authority of the nation lay with the president. The Prime Minister and the council of ministers carried out the executive function. It is the prime minister and the council of ministers that execute major policies of the government.
The constitution further created regional legislature in the four regions – the House of Assembly and the House of Chiefs. The post of a speaker and a president were created to preside over the House of Assembly and the House of Chiefs respectively.
The regional executive council was also created and a premier headed the executive council of the regions. The function of the executive council was similar to that of the council of ministers. The constitution observed the methods of sharing power between the federal government and the regions.
The 1963 republican constitution established a National Police Force for the entire federation and local government police. The Inspector General of Police became the head of the Nigeria Police Force. The Commissioners of Police headed the Nigeria Police Force at the regions.
Under the constitution, the president appointed the Chief Justice of the Supreme Court, the chief judge of Lagos and other federal justices on the recommendation of the Judicial Service Commission. The Chief Judge could be removed by the president on the approval or the recommendation of the parliament.
The Supreme Court of Nigeria became the highest court of appeal in Nigeria under the 1963 constitution. This was as a result of a dispute between the deputy leader of Action Group on one side Chief Obafemi Awolowo and the Governor of Western Region, Sir Adesoji Aderemi on the other side.
The issue as whether the governor of western region had right to dismiss the premier without the resolution of the House of Assembly. The matter came up in the high court but it was later referred to the Supreme Court for the interpretation of the constitution.
The Supreme Court held that the governor has no right to remove the premier except in the consequence of proceedings on the floor of the house in which a vote of no confidence was passed on the premier, showing that he no longer commands majority support.
The decision was appealed to the Privy Council, which reversed the decision holding that the Governor had the right. The federal government was unhappy over the decision of the Privy Council and thus went further to establish the Supreme Court as the final court of appeal in 1963.
The constitution of the 1963 provided for a procedure for altering regional boundaries. It also provided for qualification for citizenship. The constitution elaborates the fundamental rights and liberties of Nigerians in line with the 1948 UN universal declaration on human rights.
The constitution also provided for a federal and regional civil and public service. The federal Public Service Commission and Regional Public Service Commission were empowered to appoint, promote, dismiss and discipline public officers.