According to Oxford African Encyclopedia, “the constitution of a country is the body of rules and principles by which it is governed.  It states how they must be carried out. It defined the right of citizens and says how the government is to be made up”. The constitution of a country is also concerned with how decisions are reached and how powers are distributed among the various institutions of government authority,  and the methods of election and appointment of those who govern. 
Some constitutions, such as that of the United Kingdom have never been brought together and written down as a single document. Many of the United Kingdom important principles of government do not exist in written form. The constitution was not established by any single or at any precise date and it is not contained in any one document. It is contained partly in law, and partly in customs and conventions (conventions are rules or behavior accepted as obligatory in the working of a constitution). Therefore, the U.K has what is known as an UNWRITTEN OR ORAL CONSTITUTION.  
On the other hand, some countries, such as the United States of America, Nigeria and others, have what is known as a WRITTEN CONSTITUTION, this in essence, means that all the important principles of government have been brought together and written down as a single document. The Nigeria government have been brought together and written down as a single document. The Nigerian, for instance, is expected to govern according to the provisions of the Nigerian constitution, and any refusal to do that will result in the violation of the provisions of the Nigerian constitution. 


 Constitutions can be divided into two types according to the process by which they are amended. They are: flexible and rigid constitutions. 

Flexible constitutions 

Flexible constitutions are those which are passed by the law-making body in the same way as ordinary laws. It can thus be said that in this arrangement, no laws are regarded as fundamental laws.  With the flexible constitution, amendments could be made by a simple majority in the legislature. For example, the New Zealand constitution, although a written one, can be amended by a simple majority in the legislature. 

Rigid constitutions 

 In some countries, the principles enshrined in the constitution assume the character of fundamental laws. In this case, a difficult amendment procedure is adopted, so that due consideration is taken before changes are made. This condition prevents hasty alterations which political parties with temporary majorities in the legislature may be tempted to do. It also serves to protect certain racial or minority groups’ interests especially in heterogeneous societies such as the U.S.A, Nigeria and so on. For instance, a very difficult amendment procedure is adopted by the 1999 Nigeria constitution. Thus, chapter one section (9), sub-section (2) of the 1999 Nigerian constitution states that an act for alteration can only be passed in the national assembly “if  the proposal is supported by the votes of not less than two-thirds majority of all the members of the two houses, and also approved by resolution of the houses of assembly of not less than two third of all the states” . 
Constitutions may be further classified according to whether they are of the unitary, confederal or federal type. However, it should be noted that each of those types of constitutions fall in one of the two major categories discussed above. For instance, the unitary constitution is one in which all powers of government are concentrated in a single authority, i.e, central government. This single authority may then delegate powers to other subordinate authorities which, themselves, are its creation. Unitary constitution may be modified by the central government using its powers. As a result, the constitution is flexible. Examples of countries with unitary constitutions include: Britain, France and Ghana. 
The confederal constitution is another type of flexible constitution is another type of flexible constitution. A confederal constitution is one which provided for a weak centre, and strong regions. Actual powers of government lie with the component units. Examples of countries with confederal constitutions are: the common wealth independent states made up of some of the successor states to the independent states made up of some of the successor states to the defunct USSR and the former confederation of Sonegambia-made up of sovereign Senegal and Gambia. 
On the other hand, a federal constitution is one in which government powers are constitutionally shared between the central provinces and the component units known as regions, states, provinces and local governments. The constitution is supreme and does not allow for legal rights to secession by the component units. It is also rigid, making amendments to it difficult. USA, Nigeria and Canada are examples of countries with federal constitutions. 


Nigeria, like many other African countries, was colonized by Britain in 19th century. From that time, its traditional political systems were abandoned, and a new political system which relied on local chiefs to help the colonial governors to rule the country was introduced by the British. 
From 1890 onwards, nationalism began to develop, and Nigerians began to agitate for self government. The period after the Second World War,  that is, after 1945, saw even more active participation of Nigerians in the struggle for self government. This rising nationalist tide had the effect of pressurizing the colonial government to make series of constitutional changes in order to accommodate nationalist demands. Thus, many constitutions were written which attempted to make one improvement or the other on the existing institutional arrangements. 
The new political system introduced by the British began to take shape even before 1900, with the establishment of two institutions in Lagos. These institutions were the executive council and the legislative council. The executive council was composed of only Europeans, members of which included the governor of Nigeria, the colonial secretary, the treasurer and the Officer in charge of british troops in Nigeria.  The main functions of these body were: the initiation of policies, nomination of members of the legislative council and other policy matters. The legislative council on the other hand was composed of nominated Europeans an a few Africans. It’s main functions were to advise the executive council. This arrangement came under heavy criticisms by the nationalists because it gave the governor so much power, and made the nominated members just figure heads. However, since the nominated members were not elected by the people they were not even representatives of the people of Nigeria. All this resulted in the birth of the first written constitution known as hugh clifford’s constitution of 1922. 
In addition to retaining both the executive and the legislative councils, the constitution introduced changes such as providing for Nigerians in the legislative council to be elected and not nominated. It also introduced political parties as early as 1923. This constitution was, however, also criticized by the nationalists. Some of the criticisms were: 
a. That not many Nigerians were given the right to vote for the four persons which the constitution allowed. 
b. The four elected members were all from the southern part of the country 
c. Africans were not considered fit to be members of the executive council. 
The collapse of Clifford’s constitution led to the introduction of the Authur Richard”s constitution of 1946. This was an improvement of the constitution. For instance, the Richard’s constitution allowed for both Notherners and southerners to be selected to sit in the legislative council. The constitution also laid the foundation for future federalism by dividing the country into Eastern, western and Nothern regions, with each region having its own house of assembly. However, this constitution also had many defects. One of this was that members of the regional assemblies could only discuss affairs but could not take decisions. The constitution was also criticized for not increasing the number of African seats in the legislature. 
Sir Macpherson”s constitution of 1951 was the next constitution introduced. This constitution abolished the executive council and created a new body known as council of ministers, made up of representatives selected from each of the regions. The regional assemblies were given more powers. They could now make laws, although these laws were subject to the approval of the ministers. Many more changes were introduced; one of these was the renaming of the legislative council into the house of representatives, to be made up of members selected from the regional assemblies. This body was vested with the functions of debating policies and making laws for the council of ministers to approve. The constitution also reduced the powers of the governor because he was now to be assisted by the council of ministers.                                                                                                                                                                                       Although Although this constitution was an improvement over the earlier ones, it was not without some demerits, which resulted in its collapse. The fact that ministers in the council of ministers could not take conclusive decisions in their ministries meant that there were no ministerial responsibilities. The regions were only allowed to make laws on some specific issues, which had to be approved first before they could be allowed to operate. The Governor had the veto power in that he could disallow any law he did not like. All these, in addition to the regional crisis among the ministers, and the crises in the houses of representatives over the motion for self government, and so on, led to the collapse of the Macpherson’s constitutions. 
As more vigorous nationalist activities continued to be geared towars achieving self government, new constitutional arrangements had to be introduced between 1954-1966. The Oliver Liyttlton’s constitution of 1954 was the first attempt made to introduce  a real federal constitution in Nigeria. It recognized the regional assemblies and the central house of representatives by giving them concrete powers to make laws on specified items, known as excusive, residual and concurrent lists. While matters written on the excusive list were for the federal or central governments, matters on the residual list were for the regional governments and matters on the concurrent list could be handled by both regional and central governments. An important feature of this constitution was the introduction of the Premier in all the regions. There was also the introduction of more Africans in the house of representatives who replaced many white-men. However, a major defect of this constitution was the absence of a Nigerian political executive to take charge of government affairs at the central Government in Lagos. Although the office of the prime minister was created in 1957, the governor, a British nationale continued to preside over meetings of the council of ministers. The fact that a number of white-men still continued to be members of House of representatives also meant that the constitution was not truly representative of the people of Nigeria. 
Prior to the 1960 constitution, many constitutional conferences were held. In 1957, the western and eastern regions were granted self government, in 1960 it was decided that Nigeria should be fully independent, and a new constitution was approved. The 1960 constitution provided for Nigeria to become a truly federal country with a Nigerian Governor-General, who was regarded as the head of state and commander-in-chief of the Nigerian Armed forces. His functions were to appoint the prime minister, grant clemency to prisoners and also to preside at ceremonial occasions. All these functions were performed on the advice of the prime minister, who was the head of government. He was to be chairman of the cabinet or council of ministers and was given the power to appoint all ministers. 
Although the independence had been granted, there were certain features which the constitution contained which were defective. One of these was that the queen of England could still exercise power through her representative, the Governor-General. Secondly, all appeal cases in Nigeria still went up to the Judicial committee of the Privy council in the United Kingdom . all these implied that there was still a great deal of control by the colonial masters. 
Perhaps, the most significant forward match towards total political control by Nigerians was the birth of the Republican constitution of 1963. Among the aforementioned constitutions, the republican constitution was the only constitution written in Nigeria by Nigerians for Nigerians. Although not many changes were made into the 1960 constitution, the 1963 constitution made a giant stride by removing all traces of colonial connection with Britain in the constitution. Thus, the office of the Governor-General was renamed the office of the president. By this change, the president was no longer a representative of the queen, but a representative of the people of Nigeria. The constitution also put a stop to all appeal cases which hitherto went up to the Privy Council in Britain. Judicial appeal will now go to the Supreme court in Lagos. The constitution worked until 1966, when the army took over the government. 
After thirteen years of military rule, the military government set up a constitution drafting committee, whose members were drawn from all walks of life. The committee came up with the 1979 constitution to be used as from 1st October, 1979, by the civilian administration. Indeed, the 1979 constitution was a major break through in the historical development of Nigerian constitutions. The constitution contained neither racial nor regional or sectional orientation which characterized the previous constitutions. It was a constitution which provided for the federal character in all ramifications. It adopted a democratic presidential system similar to that of the United States of America. In order to enhance the unity and stability of the nation, the constitution provided for equal rights to all Nigerians without discrimination on any grounds. The constitution adopted a multi-party system and the major criterion for party registration was national character in membership and outlook. 
Prior to the drafting of the constitution more states and local government were created across the country. This provided an avenue for more people to participate in the political affairs of the nation and a more balanced representation of all the states of the federation. Thus the composition of the national assembly provided for the same number of seats to all the states in the upper house-the senate, while the lower house-the House of Representatives drew its members on the bases of population. Observes believed that this arrangement would help in preventing rational, ethnic and religious politics of the past, which ended up putting Nigerians into disunity. However, this constitution worked for only four years. In 1983, the military took over power again and suspended the use of the constitution until 1987, when the regime set up a constitution review committee to review the 1979 constitution. After certain modifications, the committee submitted its recommendation and a new constitution known as the 1989 constitution was released on 1st October 1992. It then became supreme and a guideline to the new civilian government expected to take over in 1993.  This constitution was moduled after the 1979 constitution in both style and form. However, political machinations by the General Babangida administration did not allow for the effective use of the 1989 constitution. 
The transition to civil rule came up with combined civilian and military governments. Thus, there was the national assembly comprising elected members of senate and house of representatives. All the states of the federation also had elected state governors and members of the house of assembly. Then on other extreme, there was the military head of state and the Armed forces ruling council. This arrangement was meant to be temporary, pending the election of the civilian president when the military was supposed to retire to the Barracks. As it turned out, the whole country was thrown into confusion over what law was to prevail between the constitution and the military decrees, and over which authority was the law-making organ; between the national assembly and the armed forces ruling council. This controversy reached its peak with the annulment of the june 12, presidential election. The situation was so bad that people dreaded the return of political instability of the 1960s. this chaotic political situation was the perfect excuse the military had wanted for returning to the Nigerian political scene in full swing in November, 1993. The military continued until 1999 when it handed over power to a civilian administration with a new constitution known as the 1999 constitution. 


As a matter of fact,  the 1979, the 1989 and the 1999 constitutions are similar in both style and form. The constitution is divided into eight chapters covering all the government obligations to the people and the people’s obligation to the government. 
The first chapter has two parts, the first part talks about the supremacy of the constitution, Nigeria as a federal republic, states of the federation and the federal capital territory, Abuja. Part II outlines the powers of the federal capital territory of Nigeria which include legislative powers, executive powers, judicial powers, local government system and so on. 
Chapter II is on fundamental objectives and directive principles of state policy, which include; fundamental obligations of the government and the people, political objectives, economic objectives and so on 
Nigerian citizenship comes up in chapter III. Here, the different modes of acquiring and becoming deprived of Nigerian citizenship are discussed. 
One of the fundamentals of democracy is the protection of human rights. Chapter IV of the 1999 constitution makes provision for the protection of fundamental human rights for all citizens. Such rights include: right to life, right to personal liberty, right to fair hearing, right to peaceful association and so on. Violation of such rights is a serious offence which attracts  negative sanction by the government. 
In line with its adoption of presidential democratic principles, which provide for the separation of powers and checks and balances among the three arms of government, chapter V of the 1999 constitution deals with the legislature as an arm of government, while part I of this chapter deals with the federal legislature, that the national assembly, its composition, its powers, qualification for membership, tenure of seats of members and all that is expected of this highest law-making body, part II specified similar functions for the legislature at the state level, that is, the state house of assembly. 
The constitution makes it’s provisions for the executive in chapter VI; the powers, qualifications for elections (in case of the president and vice president) and all the functions of members of the federal executive are discussed in part I, part II deals with functions of members of the state executive such as the state governors, state commissioners, members of the state civil service and chairmen of boards of state parastatals. The qualifications for membership, the powers and the functions of these officers, are clearly spelt in this section.
 A very strong element of democratic government is the judiciary. Chapter VII makes provision for the Nigerian judiciary. The first part of the chapter deals with the federal courts, while part II deals with states judiciary, and part II concerns election tribunals and so on. Nigeria courts are arranged in a hierarchical order from the highest to the lowest with each functioning within the limits of its powers given to it by the constitution. The appointment and removal of justices and judges are also stated in this section of the constitution. 
The last chapter, which is chapter VIII, provides for the federal capital territory, Abuja, which is the capital of Nigeria. This chapter also deals with general supplementary provisions such as oaths and other schedules. 
The fact that all human societies need to define relationships and set out laid down principles of behavior makes the need for constitution necessary. Whether a constitution is written or unwritten, it fulfils the same political functions in any country. Nigeria, since the beginning of nationalist movement in the 20th century has witnessed series of constitutions. Each of these constitutions tried to make one improvement or the other over the existing institutions. It is not surprising therefore, that people are agitating for a review of the current 1999 Nigerian constitution.