International security consists of the measures taken by nations and international organizations, such as the United Nations, to ensure mutual survival and safety. These measures include military action and diplomatic agreements such as treaties and conventions. International and national security are invariably linked. International security is national security or state security in the global arena.
With the end of World War II, a new subject of study focusing on international security emerged. It began as an independent field of study, but was absorbed as a sub-field of international relations. Since it took hold in the 1950s, the study of international security has been at the heart of international relations studies. It covers labels like “security studies”, “strategic studies”, “peace studies”, and others.
The meaning of "security" is often treated as a common sense term that can be understood by "unacknowledged consensus". The content of international security has expanded over the years. Today it covers a variety of interconnected issues in the world that have an impact on survival. It ranges from the traditional or conventional modes of military power, the causes and consequences of war between states, economic strength, to ethnic, religious and ideological conflicts, trade and economic conflicts, energy supplies, science and technology, food, as well as threats to human security and the stability of states from environmental degradation, infectious diseases, climate change and the activities of non-state actors.
While the wide perspective of international security regards everything as a security matter, the traditional approach focuses mainly or exclusively on military concerns.
Concepts of security in the international arena 
There is no universal definition of the concept of security. Edward Kolodziej has compared it to a Tower of Babel. Roland Paris (2004) views it as “in the eye of the beholder”. But there is a consensus that it is important and multidimensional. It has been widely applied to “justify suspending civil liberties, making war, and massively reallocating resources during the last fifty years”.
Walter Lippmann (1944) views security as the capability of a country to protect its core values, both in terms that a state need not sacrifice core values in avoiding war and can maintain them by winning war. David Baldwin (1997) argues that pursuing security sometimes requires sacrificing other values, including marginal values and prime values. Richard Ullman (1983) has suggested that a decrease in vulnerability is security.
Arnold Wolfers (1952) argues that “security” is generally a normative term. It is applied by nations “in order to be either expedient - a rational means toward an accepted end - or moral, the best or least evil course of action”. In the same way that people are different in sensing and identifying danger and threats, Wolfers argues that different nations also have different expectations of security. Not only is there a difference between forbearance of threats, but different nations also face different levels of threats because of their unique geographical, economic, ecological, and political environment.
Barry Buzan (2000) views the study of international security as more than a study of threats, but also a study of which threats that can be tolerated and which require immediate action. He sees the concept of security as not either power or peace, but something in between.
The concept of an international security actor has extended in all directions since the 1990s, from nations to groups, individuals, international systems, NGOs, and local governments.
The Multi-Sum Security Principle 
Traditional approaches to international security usually focus on state actors and their military capacities to protect national security. However, over the last decades the definition of security has been extended to cope with the 21st century globalized international community, its rapid technological developments and global threats that emerged out of this process. One such comprehensive definition has been proposed by Nayef Al-Rodhan. What he calls the "Multi-sum security principle" is based on the assumption that "in a globalized world, security can no longer be thought of as a zero-sum game involving states alone. Global security, instead, has five dimensions that include human, environmental, national, transnational, and transcultural security, and therefore, global security and the security of any state or culture cannot be achieved without good governance at all levels that guarantees security through justice for all individuals, states, and cultures."
Each of these five dimensions refers to a different set of substrates. The first dimension refers to human security, a concept that makes the principle referent object of security the individual, not the state. The second dimension is environmental security and includes issues like climate change, global warming, and access to resources. The third substrate refers to national security, defined as being linked to the state’s monopoly over use of force in a given territory and as a substrate of security that emphasizes the military and policing components of security. The fourth component deals with transnational threats such as organized crime, terrorism, and human trafficking. Finally, the integrity of diverse cultures and civilisational forms tackles the issue of transcultural security. According to this multi-faceted security framework all five dimensions of security need to be addressed in order to provide just and sustainable global security. It therefore advocates cooperative interaction between states and peaceful existence between cultural groups and civilizations.
Traditional security 
The traditional security paradigm refers to a realist construct of security in which the referent object of security is the state. The prevalence of this theorem reached a peak during the Cold War. For almost half a century, major world powers entrusted the security of their nation to a balance of power among states. In this sense international stability relied on the premise that if state security is maintained, then the security of citizens will necessarily follow. Traditional security relied on the anarchistic balance of power, a military build-up between the United States and the Soviet Union (the two superpowers), and on the absolute sovereignty of the nation state. States were deemed to be rational entities, national interests and policy driven by the desire for absolute power. Security was seen as protection from invasion; executed during proxy conflicts using technical and military capabilities.
As Cold War tensions receded, it became clear that the security of citizens was threatened by hardships arising from internal state activities as well as external aggressors. Civil wars were increasingly common and compounded existing poverty, disease, hunger, violence and human rights abuses. Traditional security policies had effectively masked these underlying basic human needs in the face of state security. Through neglect of its constituents, nation states had failed in their primary objective.
More recently, the traditional state-centric notion of security has been challenged by more holistic approaches to security. Among the approaches which seeks to acknowledge and address these basic threats to human safety are paradigms that include cooperative, comprehensive and collective measures, aimed to ensure security for the individual and, as a result, for the state.
To enhance international security against potential threats caused by terrorism and organized crime, there have been an increase in international cooperation, resulting in transnational policing. The international police Interpol shares information across international borders and this cooperation has been greatly enhanced by the arrival of the Internet and the ability to instantly transfer documents, films and photographs worldwide.
Theoretical approaches 
Classical realism 
In the field of international relations, realism has long been a dominant theory, from ancient military theories and writings of Chinese and Greek thinkers, Sun Tzu and Thucydides being two of the more notable, to Hobbes, Machiavelli and Rousseau. It is the foundation of contemporary international security studies. The twentieth century classical realism is mainly derived from Edward Hallett Carr's book The Twenty Years' Crisis. The realist views anarchy and the absence of a power to regulate the interactions between states as the distinctive characteristics of international politics. Because of anarchy, or a constant state of antagonism, the international system differs from the domestic system. Realism has a variety of sub-schools whose lines of thought are based on three core assumptions: groupism, egoism, and power-centrism. According to classical realists, bad things happen because the people who make foreign policy are sometimes bad.
Beginning in the 1960s, with increasing criticism of realism, Kenneth Waltz tried to revive the traditional realist theory by translating some core realist ideas into a deductive, top-down theoretical framework that eventually came to be called neorealism. Theory of International Politics brought together and clarified many earlier realist ideas about how the features of the overall system of states affects the way states interact:
- "Neorealism answers questions: Why the modern states-system has persisted in the face of attempts by certain states at dominance; why war among great powers recurred over centuries; and why states often find cooperation hard. In addition, the book forwarded one more specific theory: that great-power war would tend to be more frequent in multipolarity (an international system shaped by the power of three or more major states) than bipolarity (an international system shaped by two major states, or superpowers)."
Liberalism has a shorter history than realism but has been a prominent theory since World War I. It is a concept with a variety of meanings. Liberal thinking dates back to philosophers such as Thomas Paine and Immanuel Kant, who argued that republican constitutions produce peace. Kant's concept of Perpetual Peace is arguably seen as the starting point of contemporary liberal thought.
Economic liberalism 
Economic liberalism assumes that economic openness and interdependence between countries makes them more peaceful than countries who are isolated. Eric Gartzke has written that economic freedom is 50 times more effective than democracy in creating peace. Globalization has been important to economic liberalism.
Liberal institutionalism 
Liberal institutionalism views international institutions as the main factor to avoid conflicts between nations. Liberal institutionalists argue that; although the anarchic system presupposed by realists cannot be made to disappear by institutions; the international environment that is constructed can influence the behavior of states within the system. Varieties of international governmental organizations (IGOs) and international non-governmental organizations (INGOs) are seen as contributors to world peace.
Comparison between realism and liberalism 
|Theoretical base||Realist (alliance)||Liberal (community of law)|
|Structure of the international system||Material; static; anarchic; self-help system||Social; dynamic; governance without government|
|Conceptions of security||Basic principles||Accumulation of power||Integration|
|Strategies||Military deterrence; control of allies||Democratization; conflict resolution; rule of Law|
|Institutional features||Functional scope||Military realm only||Multiple issue areas|
|Criterion for membership||Strategic relevance||Democratic system of rule|
|Internal power structure||Reflects distribution of power; most likely hegemonic||Symmetrical; high degree of interdependence|
|Decision-making||Will of dominant power prevails||Democratically legitimized|
|Relation of system to its environment||Dissociated; perception of threat||Serves as an attractive model; open for association|
Since its founding in the 1980s, constructivism has become an influential approach in international security studies. “It is less a theory of international relations or security, however, than a broader social theory which then informs how we might approach the study of security.” Constructivists argue that security is a social construction. They emphasize the importance of social, cultural and historical factors, which leads to different actors construing similar events differently.
Prominent thinkers 
Barry Buzan – Copenhagen School
Alexander Wendt – Constructivism
Edward Hallett Carr – Classical realism
Hans J. Morgenthau – Classical realism
Immanuel Kant – Kantian liberalism
John Mearsheimer – Neorealism
Joseph Nye – Liberal institutionalism
Kathryn Sikkink – Constructivism
Kenneth Waltz – Neorealism
Machiavelli – Classical realism
Nayef Al-Rodhan – Symbiotic Realism
Peter J. Katzenstein – Constructivism
Robert Axelrod – Liberal institutionalism
Robert Gilpin – Neorealism
Robert Jervis – Neorealism
Robert Keohane – Liberal institutionalism
Thomas Hobbes – Classical realism
Thucydides – Classical realism
Human security 
Human security derives from the traditional concept of security from military threats to the safety of people and communities. It is an extension of mere existence (survival) to well-being and dignity of human beings. Human security is an emerging school of thought about the practice of international security. There is no single definition of human security, it varies from “ a narrow term of prevention of violence to a broad comprehensive view that proposes development, human rights and traditional security together.” Critics of the concept of human security claim that it covers almost everything and that it is too broad to be the focus of research. There have also been criticisms of its challenge to the role of states and their sovereignty.
Human security offers a critique of and advocates an alternative to the traditional state-based conception of security. Essentially, it argues that the proper referent for security is the individual and that state practices should reflect this rather than primarily focusing on securing borders through unilateral military action. The justification for the human security approach is said to be that the traditional conception of security is no longer appropriate or effective in the highly interconnected and interdependent modern world in which global threats such as poverty, environmental degradation, and terrorism supersede the traditional security threats of interstate attack and warfare. Further, state-interest-based arguments for human security propose that the international system is too interconnected for the state to maintain an isolationist international policy. Therefore, it argues that a state can best maintain its security and the security of its citizens by ensuring the security of others. It is need to be noted that without the traditional security no human security can be assured.
|Type of security||Referent||Responsibility||Threats|
|Traditional||The state||Integrity of the state||Interstate war, nuclear proliferation, revolution, civil conflict|
|Human||The individual||Integrity of the individual||Disease, poverty, natural disaster, violence, landmines, human rights abuses|
UNDP human security proposal 
- Investing in human development, not in arms;
- Engaging policy makers to address the emerging peace dividend;
- Giving the United Nations a clear mandate to promote and sustain development;
- Enlarging the concept of development cooperation so that it includes all flows, not just aid;
- Agreeing that 20 percent of national budgets and 20 percent of foreign aid be used for human development; and
- Establishing an Economic Security Council.
The report elaborates on seven components to human security. Tadjbakhsh and Chenoy list them as follows:
|Type of security||Definition||Threats|
|Economic security||An assured basic income||Poverty, unemployment, indebtedness, lack of income|
|Food security||Physical and economic access to basic food||Hunger, famines and the lack of physical and economic access to basic food|
|Health security||Protection from diseases and unhealthy lifestyles||Inadequate health care, new and recurrent diseases including epidemics and pandemics, poor nutrition and unsafe environment, unsafe lifestyles|
|Environmental security||Healthy physical environment||Environmental degradation, natural disasters, pollution and resource depletion|
|Personal security||Security from physical violence||From the state (torture), other states (war), groups of people (ethnic tension), individuals or gangs (crime), industrial, workplace or traffic accidents|
|Community security||Safe membership in a group||From the group (oppressive practices), between groups (ethnic violence), from dominant groups (e.g. indigenous people vulnerability)|
|Political security||Living in a society that honors basic human rights||Political or state repression, including torture, disappearance, human rights violations, detention and imprisonment|
See also 
- Buzan, B. and L. Hansen (2009). The Evolution of International Security Studies. Cambridge, Cambridge University Press.
- Sheehan, M. (2005). International Security: An Analytical Survey. London, Lynne Rienner Publishers.
- Sheehan, M. (2005), International Security: and Analytical Survey, London, Lynne Rienner Publishers
- Buzen, B., O. Wæver, et al. (1998). Security: A new frame work for Analysis. Boulder, CO, Lynne Rienner Publishers.; Doty, P., A. Carnesale, et al. (1976). "Foreword." International Security 1(1).
- Kolodziej, E. (2005). Security and International Relations. Cambridge, Cambridge University Press.P.11
- Paris, R. (2004). "Still and Inscrutable Concept", Security Dialogue 35: 370-372.
- Baldwin, D. (1997). "The concept of Security." Review of International studies 23: 5-26
- Lippmann, W. (1944). U.S. Foreign Policy. London, Hamish Hamilton
- Ullman, R. (1983). "Redefining Security." International Security 8(1): 129-153
- Wolfers, A. (1952). ""National Security" as an Ambiguous Symbol." Political Science Quarterly 67(4): 481-502.
- Buzan, B. (2000). 'Change and Insecurity' reconsidered. Critical Reflection on Security and Change. S. Croft and T. Terriff. Oxen, Frank Cass Publishers.
- Buzan, B. (2007). People, States & Fear. Colchester, ECPR.
- Rothschild, E. (1995). "What is Security." Dædalus 124(3): 53-98.
- Al-Rodhan, Nayef R.F., The Five Dimensions of Global Security: Proposal for a Multi-sum Security Principle, LIT, 2007
- Bajpai, K. 2000, Human Security: Concept and Measurement, University of Notre Dame, Kroc Institute Occasional Paper no. 19 Accessed 29/04/06 at: <www.nd.edu/~krocinst/ocpapers/op_19_1.PDF
- Owen, T. (2004), Challenges and opportunities for defining and measuring human security’, Human Rights, Human Security and Disarmament, Disarmament Forum. 3, 15-24
- J. Baylis, 1997, International Security in the Post-Cold War Era, in John Baylis and Steve Smith (eds), The Globalization of World Politics, Oxford, Oxford University Press.
- Strategy and Ethnic Conflict (ISBN 027597636X) and Path to Peace (ISBN 1590337328) among many others)
- Elman, C. (2008). Realism. Security Studies:and Introduction. P. D. William. New York, Routledge.
- Morgan, P. (2007). Security in International Politics: Traditional Approaches. Contemporary Security Studies. A. Collins. New York, Oxford University Press.
- Wohlforth, W. C. (2010). Realism and Security Studies. The Routledge Handbook of Security Studies. M. D. Cavelty and V. Mauer. New York, Routledge.
- Elman, C. (2008). Realism. Security Studies: An Introduction. P. D. William. New York, Routledge.
- Waltz, K. Z. (1979). Theory of International Politics. New York, Random House.
- The Oxford Handbook of International Relations. Oxford University Press. 2008. p. 137. ISBN 978-0-19-921932-2.
- Navari, C. (2008). Liberalism. Security Studies: An Introduction. P. D. William. New York, Routledge.;Rousseau, D. L. (2010). Liberalism. The Routledge Handbook of Security Studies. M. D. Cavelty and V. Mauer. New York, Routledge.
- Gartzke, E. (2005), 'Economic Freedom and Peace' in Economic Freedom of the World, Annual Report. pp. 29-44
- Navari, C. (2008). Liberalism. Security Studies: An Introduction. P. D. William. New York, Routledge.
- Elman, C. (2008). Realism. Security Studies: An Introduction. P. D. William. New York, Routledge. p. 42.
- McDonald, M. (2008). Constructivism. Security Studies: an Introduction. P. D. William. New York, Routledge.
- Tadjbakhsh, S. and A. Chenoy (2007). Human Security: Concepts and Implications. New York, Routledge.
- UNDP (1994). Human Development Report, http://hdr.undp.org/en/reports/global/hdr1994/chapters/
- Tadjbakhsh, S. and A. Chenoy (2007). Human Security: Concepts and Implications. New York, Routledge. pp. 128-129.
- The European Union Institute for Security Studies
- Evolution in international security through the United Nations: The presentation of the Eurocorps-Foreign Legion concept at the European Parliament in June 2003
- Center on Conflict, Development and Peacebuilding, Graduate Institute of International and Development Studies
- Center for International Security Studies
- Centre for International Studies (Security|IR)