A great power is a nation or state that has the ability to exert its influence on a global scale. Great powers characteristically possess military and economic strength and diplomatic and cultural influence which may cause small powers to consider the opinions of great powers before taking actions of their own. International relations theorists have posited that great power status can be characterized into power capabilities, spatial aspects, and status dimensions
There are no set or defined characteristics of a great power. These characteristics have often been treated as empirical, self-evident to the assessor.[9] However, this approach has the disadvantage of subjectivity. As a result, there have been attempts to derive some common criteria and to treat these as essential elements of great power status.
Early writings on the subject tended to judge states by the realist criterion, as expressed by the historian A. J. P. Taylor when he noted that "The test of a great power is the test of strength for war." Later writers have expanded this test, attempting to define power in terms of overall military, economic, and political capacity. Kenneth Waltz, the founder of the neorealist theory of international relations, uses a set of five criteria to determine great power: population and territory; resource endowment; economic capability; political stability and competence; and military strength. These expanded criteria can be divided into three heads: power capabilities, spatial aspects, and status.
For many, power capabilities were the sole criterion.
Duroselle : "A Great power is one which is capable of preserving its own independence against any other single power
Ranke: a Great power that it must be able to maintain itself against all others, even when they are united
All states have a geographic scope of interests, actions, or projected power. This is a crucial factor in distinguishing a great power from a regional power; by definition the scope of a regional power is restricted to its region. It has been suggested that a great power should be possessed of actual influence throughout the scope of the prevailing international system. Other suggestions have been made that a great power should have the capacity to engage in extra-regional affairs and that a great power ought to be possessed of extra-regional interests, two propositions which are often closely connected
Formal or informal acknowledgment of a nation's great-power status has also been a criterion for being a great power.
