2. The concept “national interest” is a very complex word
The concept “national interest” is a very complex word. Hence, there is no generally accepted definition of the concept. Scholars however, have put forward various definitions of the concept based on their understanding. They have also argued about how to determine national interest or who actually determines national interest. Competition to define the national interest is often intense, because while the goals and values that a state may pursue are virtually endless, the same is not true for the resources needed to realise them. Decisions must constantly be made about which goals to emphasis and which to neglect.

3. The definition given to the national interest is a major factor affecting which values will be favored. This is because not all foreign policies (and, therefore, the values that they protect) are compatible with a given definition of national interest.
Foreign policy has been defined as the specified goals that leaders pursue in the international system, the values that shape those specific goals and the means by which those goals are achieved. Foreign policies are justified because they further the national interest. Yet, as was the case with U.S foreign policy in Vietnam, invoking the “national interest” seldom ends disagreement over the wisdom of a course of action.

4. Controversies over the Meaning of National Interest :
Why do governments do the things they do and do not do the things they seemingly could do? The answer is usually “national interest”. When Winston Churchill was asked for an explanation of Soviet behavior, he replied “I cannot forecast to you the actions of Russia. It is a riddle wrapped in a mystery inside an enigma, but perhaps there is a key. That key is Russian national interest (Kennedy, 1987).

5. National interests are evoked to justify virtually every act of a state, from generosity to genocide. And some states follow policies that in retrospect undermine rather than enhance national interests. The imperialism of Germany, Japan and Italy during the 1930s and 1940s, or Iraq’s invasion of Kuwait in August 1990 was justified by the leaders of those countries as being in their national interest. But imperialism left those nations in ruins.

6. Consequently, national interest is an elusive term which has been described in various ways. Kaplan (1967) for instance, defines it as the interest, which a national actor has in implementing a defined system of action. Morgenthau (1967) conceives(ideate) of it simply as politics among nations. To Jones (1970), national interest is a term used in political debate within a country, to signal the case that the item of policy suggested will bring benefits not merely to its proponents but also to its opponents.

7. Frankel (1972), assumption that national interest is a key concept in foreign policy. In his view, it amounts to the total of all national values, national in both meaning of the word, both relating to the nation and the state. One general common sense definition describes it as the general and continuing ends for which a nation acts. This presupposes that every nation has a set of objectives or goals which gives life and meaning to the behavior of such nation in international relations.

8. Some of these objectives or goals are central to the survival of the nation, while others are not so central to it, even though they are integrated within the large interest of the international community. Strictly speaking, every nation strives to protect, promote and defend its objectives at all cost even to the point of going to war, if it felt that the pursuits of these objectives or goals are threatened. Hence, the totality of these objectives or goals is what constitutes(formalizes) national interest.

9. All states share some common interests-political independence, economic growth, cultural preservation, peace etc. The most obvious
national interest is self- preservation, and the greatest threat to that basic interest is for another state to invade and conquer it. The threat of foreign invasion are however, increasingly rare in international relations, since the end of the Cold War. Three other “core national values” in diminishing importance are the enhancement of a nation’s economic development, independence from the interference of others in one’s domestic affair, and preservation of the nations “way of life or culture”.

10. It is pertinent to note that in reality national interest is conducted, directed or determined by the ruling class or the political elites. It is the power that the (incumbent(have to) government most times) uses to select, pursue, or operationalize what a nation’s national interest is.
National interest, apart from all else is useful for analytical purposes as it is a yardstick for actors in the international system. However, if the nations of the world do nothing but to rationalize their actions on the basis of parochial national interest, there would be more crises than what now obtains.

11. The philosophy surrounding the concept is increasingly becoming devalued, given increasingly interdependence of states, as well as the emergence of non-state actors, who somewhat de-emphasize state centrism, and have been flagrantly and recklessly disregarding tradition and order of things concerning inter-state interactions.

13. Linkage Between National Interest and Foreign Policy
Foreign policies are justified because they further the national interests of nation-states. Although national interest is an ambiguous concept and therefore limited in its ability to guide policy,

14. it is not altogether lacking in meaning and action
it is not altogether lacking in meaning and action. It directs the attention of policymakers to a category of goals that a state’s foreign policy should value most, national or societal goals.

15. Goals that advance only the interests of certain individuals or groups are by definition, not eligible for placement at the center of a state’s foreign policy. For a foreign policy goal or objective to be in the national interest, it must benefit more than a particular group or sector; it must promote the welfare of the country as a whole.

16. It must be stressed however that the articulation of the goals does not necessarily guarantee the successful execution of foreign policy. The extent to which a foreign policy goal/objective is achieved depends largely on the quality,

17. character and disposition of policy makers, the prevailing political and economic circumstances, the resource endowments of the state, the military capability, geographical location, population and a host of other factors.

18. The foreign policy of every country is at all times presumably designed to promote the national interest. As the national interest does not exist in abstraction, the quest(pursuit) of policy makers should therefore be how to identify and serve the national interest. This involves what is national, since there are many national interests in a particular situation

19. It must be stressed however that the articulation of the goals does not necessarily guarantee the successful execution of foreign policy. The extent to which a foreign policy goal/objective is achieved depends largely on the quality,

20. character and disposition(arrange) of policy makers, the prevailing(sovereignty) political and economic circumstances, the resource endowments of the state, the military capability, geographical location, population and a host of other factors.

21. CONCLUSION :
The formation and execution of foreign policy is determined to a large extent by the national interest of a nation. National interest is a key concept in foreign policy. It amounts to the sum total of all the national values.

22. . National interest is the general and continuing ends for which a nation formulates and executes foreign policy. This presupposes that every nation has a set of objectives or goals which gives life and meaning to the behavior of such nation in international relations.