And nations try to safeguard their interest by trying to control and influence the behaviour of other nations. National interests , however is served through foriegn policy . Thus nation come into contact with each other through foriegn policies.The relationship between India and china were most cordial and friendly , for more than a decade. But since 1959 and especially after 1962 ,two countries have been involved in conflict as serious nature. From my view point of study ,the present phrase of sino-India relation is more important subject of study than all early phrases. Nations arrange their priorities on the basis of their resources. Security has been seen to be the most important of these priorities. Powerful nations with worldwide political, economic and military activities like that of the US and the Soviet Union, placed high priority on security, while smaller nations with limited interests and limited resources, such as Switzerland and Sweden, pursued their own interests and diplomatically protected them. These limited resources compel the nations to reorder priorities. No nation has unlimited resources, so priorities have to be ordered.For example, a nation threatened by its neighbours puts security on the top of its agenda, but a nation which is relatively secure, may concentrate on its economic development. Great Britain sacrificed problems after the Second World War. General Charles de Gaulle concentrated on nuclear weapons, development programmes to restore France to the status of one of the most powerful nations. So nations order their priorities in such a way that foreign policy decisions can be based on realistic projections in domestic politics as well as international politics. These priorities are the components of national interests. All nations have their minimum acceptable level of economic sufficiency. Obviously, the protection and improvement of that standard becomes a part of that national interest. The Arab states’ use of oil as a diplomatic weapon in their conflict with Israel, forced many nations to reassess their foreign policy priorities. In the aftermath of the Arab oil embargo, many nations, normally friendly to Israel, have decided that their national interests were better served by having access to il. It must be mentioned that national interests of countries are likely to change due to various factors. It could be due to change in governments or interests of the most influential groups or a general change in the international situation. Like the onset of globalization or the shift from bipolarity to a multipolar world. The national interests of a state are divided into vital interests and non-vital interests. Vital interests are those for which the state is not willing to make any compromise and is even prepared to go to war. They are also regarded as permanent or primary.It includes the protection of territorial integrity or sometimes, national prestige. These vital interests undergo changes due to various reasons. Many times, vital interests are defined according to the selfish interests of the nations, without taking into consideration the international norms. This is true, more in case of the great powers. These priorities are the components of national interests. All nations have their minimum acceptable level of economic sufficiency. Obviously, the protection and improvement of that standard becomes a part of that national interest. The US interventions in Vietnam, West Asia and Afghanistan were regarded as necessary for the protection of its vital interests. The interests that are considered as less vital or secondary are those for which they would not go to war but want to see them fulfilled, such as improvement in trade or cultural contacts. Vital interests may be described as the goals and the secondary interests as the objectives of foreign policy.