Peace

Peace is a concept of societal friendship and harmony in the absence of hostility and violence. In a social sense, peace is commonly used to mean a lack of conflict (such as war) and freedom from fear of violence between individuals or groups. Throughout history, leaders have used peacemaking and diplomacy to establish a type of behavioral restraint that has resulted in the establishment of regional peace or economic growth through various forms of agreements or peace treaties. Such behavioral restraint has often resulted in reduced conflict, greater economic interactivity, and consequently substantial prosperity.

"Psychological peace" (such as peaceful thinking and emotions) is perhaps less well defined, yet often a necessary precursor to establishing "behavioral peace." Peaceful behavior sometimes results from a "peaceful inner disposition." Some have expressed the belief that peace can be initiated with a certain quality of inner tranquility that does not depend upon the uncertainties of daily life. The acquisition of such a "peaceful internal disposition" for oneself and others can contribute to resolving otherwise seemingly irreconcilable competing interests. Peace is not a state of excitement although we are happy when excited, peace is when one's mind is quiet and satisfied.
Etymology

Before the word 'peace' came into the English lexicon, Anglo-Saxons used the phrase "friðu sibb" for 'pledge of peace'

The term 'peace' originates most recently from the Anglo-French pes, and the Old French pais, meaning "peace, reconciliation, silence, the agreement" (11th century).] The Anglo-French term pes itself comes from the Latin pax, meaning "peace, compact, agreement, treaty of peace, tranquility, absence of hostility, harmony." The English word came into use in various personal greetings from c.1300 as a translation of the Hebrew word shalom, which, according to Jewish theology, comes from a Hebrew verb meaning 'to be complete, whole. Although 'peace' is the usual translation, however, it is an incomplete one, because 'shalom,' which is also cognate with the Arabic salaam, has multiple other meanings in addition to peace, including justice, good health, safety, well-being, prosperity, equity, security, good fortune, and friendliness, as well as simply the greetings, "hello" and "goodbye". On a personal level, peaceful behaviors are kind, considerate, respectful, just, and tolerant of others' beliefs and behaviors – tending to manifest goodwill.

This latter understanding of peace can also pertain to an individual's introspective sense or concept of her/himself, as in being "at peace" in one's own mind, as found in European references from c.1200. The early English term is also used in the sense of "quiet", reflecting calm, serene, and meditative approaches to family or group relationships that avoid quarreling and seek tranquility — an absence of disturbance or agitation.

In many languages, the word for peace is also used as a greeting or a farewell, for example, the Hawaiian word aloha, as well as the Arabic word salaam. In English, the word peace is occasionally used as a farewell, especially for the dead, as in the phrase rest in peace.

Wolfgang Dietrich, in his research project which led to the book The Palgrave International Handbook of Peace Studies (2011), maps the different meanings of peace in different languages and regions across the world. Later, in his Interpretations of Peace in History and Culture (2012), the groups the different meanings of peace into five peace families: Energetic/Harmony, Moral/Justice, Modern/Security, Postmodern/Truth, and Transrational, a synthesis of the positive sides of the four previous families and the society.
History

Crossed coin of Croesus c.550 BC, depicting the Lion and Bull – partly symbolizing alliance between Lydia and Greece, respectively.

In ancient times and more recently, peaceful alliances between different nations were codified through royal marriages. Two examples, Hermodike I c.800BC[7] and Hermodike II c.600BC[8] were Greek princesses from the house of Agamemnon who married kings from what is now Central Turkey. The union of Phrygia / Lydia with Aeolian Greeks resulted in regional peace, which facilitated the transfer of ground-breaking technological skills into Ancient Greece; respectively, the phonetic written script and the minting of coinage (to use a token currency, where the value is guaranteed by the state).[9] Both inventions were rapidly adopted by surrounding nations through further trade and cooperation and have been of fundamental benefit to the progress of civilization.

Throughout history, victors have sometimes used ruthless measures to impose peace upon the vanquished. In his book Agricola, the Roman historian Tacitus includes eloquent and vicious polemics against the rapacity and greed of Rome. One, that Tacitus says is by the Caledonian chieftain Calgacus ends with Auferre trucidare rapere falsis nominibus imperium, atque Ubi solitudinem faciunt, pacem appellant. (To ravage, to slaughter, to usurp under false titles, they call empire; and where they make a desert, they call it peace. — Oxford Revised Translation).

Discussion of peace is therefore at the same time a discussion of its form. Is it simply the absence of mass organized killing (war), or does peace require a particular morality and justice? (just peace).[10] Peace must be seen at least in two forms: A simple silence of arms, and the absence of war.
The absence of war is accompanied by particular requirements for the mutual settlement of relations, which are characterized by terms such as justice, mutual respect, respect for the law, and goodwill.

More recently, advocates for radical reform in justice systems have called for a public policy adoption of non-punitive, non-violent Restorative Justice methods. Many of those studying the success of these methods, including a United Nations working group on Restorative Justice Archived 26 July 2011 at the Wayback Machine, have attempted to redefine justice in terms related to peace. From the late 2000s on, a Theory of Active Peace has been proposed[11] which conceptually integrates justice into a larger peace theory.

Another internationally important approach to peace is the international, national and local protection of cultural assets in the event of conflicts. United Nations, UNESCO, and Blue Shield International deal with the protection of cultural heritage. This also applies to the integration of United Nations peacekeeping. UNESCO Director-General Irina Bokova stated: "The protection of culture and heritage is a humanitarian and security policy imperative that also paves the way for resilience, reconciliation, and peace." The protection of the cultural heritage should preserve the particularly sensitive cultural memory, the growing cultural diversity, and the economic basis of a state, a municipality, or a region. In many conflicts, there is a deliberate attempt to destroy the opponent's cultural heritage. Whereby there is also a connection between cultural user disruption or cultural heritage and the cause of flight. However, protection can only be implemented sustainably through the fundamental cooperation and training of military units and civilian personnel, together with the locals. The president of Blue Shield International Karl von Habsburg summed it up with the words: “Without the local community and without the local participants, that would be completely impossible”.[12][13][14][15][16][17]
Organizations and prizes
United Nations

UN peacekeeping missions. Dark blue regions indicate current missions, while light blue regions represent former missions.
Main article: United Nations
See also: List of United Nations peacekeeping missions

The United Nations (UN) is an international organization whose stated aims are to facilitate cooperation in international law, international security, economic development, social progress, human rights, and achieving world peace. The UN was founded in 1945 after World War II to replace the League of Nations, to stop wars between countries, and to provide a platform for dialogue.

After authorization by the Security Council, the UN sends peacekeepers to regions where armed conflict has recently ceased or paused to enforce the terms of peace agreements and to discourage combatants from resuming hostilities. Since the UN does not maintain its own military, peacekeeping forces are voluntarily provided by member states of the UN. The forces also called the "Blue Helmets", who enforce UN accords are awarded United Nations Medals, which are considered international decorations instead of military decorations. The peacekeeping force as a whole received the Nobel Peace Prize in 1988.
Police
Main article: Police

The obligation of the state to provide for domestic peace within its borders is usually charged to the police and other general domestic policing activities. The police are a constituted body of persons empowered by a state to enforce the law, protect the lives, liberty, and possessions of citizens, and prevent crime and civil disorder.[18] Their powers include the power of arrest and the legitimized use of force. The term is most commonly associated with the police forces of a sovereign state that are authorized to exercise the police power of that state within a defined legal or territorial area of responsibility. Police forces are often defined as being separate from the military and other organizations involved in the defense of the state against foreign aggressors; however, the gendarmerie is a military unit charged with civil policing.[19] Police forces are usually public sector services, funded through taxes.
National security[edit]
Main article: National security

National security must provide for peace and security in a nation against foreign threats and foreign aggression. Potential causes of national insecurity include actions by other states (e.g. military or cyber attack), violent non-state actors (e.g. terrorist attacks), organized criminal groups such as narcotic cartels, and also the effects of natural disasters (e.g. flooding, earthquakes).[20]: v, 1–8 [21] Systemic drivers of insecurity, which may be transnational, include climate change, economic inequality and marginalization, political exclusion, and militarisation.[21] Given the wide range of risks, the preservation of peace and the security of a nation-state have several dimensions, including economic security, energy security, physical security, environmental security, food security, border security, and cyber security. These dimensions correlate closely with elements of national power.
League of Nations[edit]

The principal forerunner of the United Nations was the League of Nations. It was created at the Paris Peace Conference of 1919 and emerged from the advocacy of Woodrow Wilson and other idealists during World War I. The Covenant of the League of Nations was included in the Treaty of Versailles in 1919, and the League was based in Geneva until its dissolution as a result of World War II and replacement by the United Nations. The high hopes widely held for the League in the 1920s, for example amongst members of the League of Nations Union, gave way to widespread disillusion in the 1930s as the League struggled to respond to challenges from Nazi Germany, Fascist Italy, and Japan.

One of the most important scholars of the League of Nations was Sir Alfred Eckhard Zimmern. Like many of the other British enthusiasts for the League, such as Gilbert Murray and Florence Stawell – known as the "Greece and peace" set – he came to this from the study of the classics.

The creation of the League of Nations, and the hope for informed public opinion on international issues (expressed for example by the Union for Democratic Control during World War I), also saw the creation after World War I of bodies dedicated to understanding international affairs, such as the Council on Foreign Relations in New York and the Royal Institute of International Affairs at Chatham House in London. At the same time, the academic study of international relations started to professionalize, with the creation of the first professorship of international politics, named for Woodrow Wilson, at Aberystwyth, Wales, in 1919.
Olympic Games

The late 19th-century idealist advocacy of peace which led to the creation of the Nobel Peace Prize, the Rhodes Scholarships, the Carnegie Endowment for International Peace, and ultimately the League of Nations, also saw the re-emergence of the ancient Olympic ideal. Led by Pierre de Coubertin, this culminated in the holding in 1896 of the first of the modern Olympic Games.
Nobel Peace Prize
Main article: Nobel Peace Prize

Henry Dunant was awarded the first-ever Nobel Peace Prize for his role in founding the International Red Cross.

The highest honor awarded to peacemakers is the Nobel Prize in Peace, awarded in 1901 by the Norwegian Nobel Committee. It is awarded annually to internationally notable persons following the prize's creation in the will of Alfred Nobel. According to Nobel's will, the Peace Prize shall be awarded to the person who "...shall have done the most or the best work for fraternity between nations, for the abolition or reduction of standing armies, and for the holding and promotion of peace congresses."[22]
Rhodes, Fulbright, and Schwarzman scholarships

In creating the Rhodes Scholarships for outstanding students from the United States, Germany, and much of the British Empire, Cecil Rhodes wrote in 1901 that 'the object is that an understanding between the three great powers will render war impossible and educational relations make the strongest tie'.[23] This peace purpose of the Rhodes Scholarships was very prominent in the first half of the 20th century, and became prominent again in recent years under Warden of the Rhodes House Donald Markwell,[24] a historian of thought about the causes of war and peace.[25] This vision greatly influenced Senator J. William Fulbright in the goal of the Fulbright fellowships to promote international understanding and peace and has guided many other international fellowship programs,[26] including the Schwarzman Scholars to China created by Stephen A. Schwarzman in 2013.[27]
Gandhi Peace Prize
Main article: Gandhi Peace Prize

Mahatma Gandhi.

The International Gandhi Peace Prize, named after Mahatma Gandhi, is awarded annually by the Government of India. It was launched as a tribute to the ideals espoused by Gandhi in 1995 on the occasion of the 125th anniversary of his birth. This is an annual award given to individuals and institutions for their contributions toward social, economic, and political transformation through non-violence and other Gandhian methods. The award carries Rs. 10 million in cash, a convertible in any currency in the world, a plaque, and a citation. It is open to all persons regardless of nationality, race, creed, or sex.
Student Peace Prize
Main article: Student Peace Prize

The Student Peace Prize is awarded biennially to a student or a student organization that has made a significant contribution to promoting peace and human rights.
Culture of Peace News Network
Main article: Culture of Peace News Network

The Culture of Peace News Network, otherwise known simply as CPNN, is an UN-authorized interactive online news network, committed to supporting the global movement for a culture of peace.

Rainbows: Often used as a symbol of harmony and peace.
Sydney Peace Prize

Every year in the first week of November, the Sydney Peace Foundation presents the Sydney Peace Prize. The Sydney Peace Prize is awarded to an organization or an individual whose life and work have demonstrated significant contributions to:
The achievement of peace with justice locally, nationally, or internationally
The promotion and attainment of human rights
The philosophy, language, and practice of non-violence
Museums
See also: Peace museums

A peace museum is a museum that documents historical peace initiatives. Many provide advocacy programs for nonviolent conflict resolution. This may include conflicts at the personal, regional or international level.

Smaller institutions include the Randolph Bourne Institute, the McGill Middle East Program of Civil Society and Peace Building, and the International Festival of Peace Poetry.
Religious beliefs

Religious beliefs often seek to identify and address the basic problems of human life, including conflicts between, among, and within persons and societies. In ancient Greek-speaking areas, the virtue of peace was personified as the goddess Eirene, and in Latin-speaking areas as the goddess Pax. Her image was typically represented by ancient sculptors as a full-grown woman, usually with a horn of plenty and scepter and sometimes with a torch or olive leaves.
Christianity

The Kind Angel of Peace monument in the city of Donetsk, Ukraine, by Russian artist Peter Stransky

Christians, who believe Jesus of Nazareth to be the Jewish Messiah called Christ (meaning Anointed One),[28] interpret Isaiah 9:6 as a messianic prophecy of Jesus in which he is called the "Prince of Peace."[29] In the Gospel of Luke, Zechariah celebrates his son John: And you, child, will be called the prophet of the Highest, for you will go before the Lord to prepare his ways, to give his people knowledge of salvation through the forgiveness of their sins, because of the tender mercy of our God by which the daybreak from on high will visit us to shine on those who sit in darkness and death's shadow, to guide our feet into the path of peace.

As a testimony of peace, Churches of the Anabaptist Christian tradition (such as the Mennonites), as well as Holiness Methodist Pacifists (such as the Immanuel Missionary Church) and Quakers (such as the Conservative Friends), practice nonresistance and do not participate in warfare.[30][31]

In the Catholic Church, numerous pontifical documents on the Holy Rosary document a continuity of views of the Popes to have confidence in the Holy Rosary as a means to foster peace. Subsequently, in the Encyclical Mense Maio,1965, in which he urged the practice of the Holy Rosary, "the prayer so dear to the Virgin and so much recommended by the Supreme Pontiffs," and as reaffirmed in the encyclical Christi Matri, 1966, to implore peace, Pope Paul VI stated in the apostolic Recurrens mensis, October 1969, that the Rosary is a prayer that favors the great gift of peace.
Hinduism

Hindu texts contain the following passages:


May there be peace in the heavens, peace in the atmosphere, peace on the earth. Let there be coolness in the water, healing in the herbs, and peace radiating from the trees. Let there be harmony in the planets and in the stars, and perfection in eternal knowledge. May everything in the universe be at peace. Let peace pervade everywhere, at all times. May I experience that peace within my own heart?
— Yajur Veda 36.17)


Let us have concord with our own people, and concord with people who are strangers to us. Ashwins (Celestial Twins,) create between us and the strangers a unity of hearts. May we unite in our minds, unite in our purposes, and not fight against the heavenly spirit within us. Let not the battle-cry rise amidst many slain, nor the arrows of the war-god fall with the break of day
— Yajur Veda 7.52


A superior being does not render evil for evil. This is a maxim one should observe... One should never harm the wicked or the good or even animals meriting death. A noble soul will exercise compassion even towards those who enjoy injuring others or cruel deeds... Who is without fault?
— Valmiki, Ramayana


The chariot that leads to victory is of another kind. Valor and fortitude are its wheels; Truthfulness and virtuous conduct are its banners; Strength, discretion, self-restraint, and benevolence are its four horses, Harnessed with the cords of forgiveness, compassion, and equanimity...Whoever has this righteous chariot, has no enemy to conquer anywhere.
— Valmiki, Ramayana
Buddhism

Buddhists believe that peace can be attained once all suffering ends. They regard all suffering as stemming from cravings (in the extreme, greed), aversions (fears), or delusions. To eliminate such suffering and achieve personal peace, followers in the path of the Buddha adhere to a set of teachings called the Four Noble Truths — a central tenet in Buddhist philosophy.
Islam

Islam is derived from the root word salam which literally means peace. Muslims are called followers of Islam. Quran clearly stated "Those who have believed and whose hearts are assured by the remembrance of Allah. Unquestionably, by the remembrance of Allah, hearts are assured" and stated "O you who have believed, when you are told, "Space yourselves" in assemblies, then make space; Allah will make space for you. And when you are told, "Arise," then arise; Allah will raise those who have believed among you and those who were given knowledge, by degrees. And Allah is Acquainted with what you do."[32][33]
Judaism

The Judaic tradition directly associates God with peace, as evidenced by various principles and laws in Judaism. Shalom, the biblical and modern Hebrew word for peace, is one of the names for God according to the Judaic law and tradition. For instance, in traditional Jewish law, individuals are prohibited from saying "Shalom" when they are in the bathroom as there is a prohibition on uttering any of God's names in the bathroom, out of respect for the divine name. Jewish liturgy and prayer are replete with prayers asking God to establish peace in the world. The Shmoneh Esreh, a key prayer in Judaism that is recited three times each day, concludes with a blessing for peace. The last blessing of the Shmoneh Esreh, also known as the Amida ("standing" as the prayer is said while standing), is focused on peace, beginning and ending with supplications for peace and blessings. Peace is central to Judaism's core principle of Moshiach ("messiah") which connotes a time of universal peace and abundance, a time where weapons will be turned into plowshares and lions will sleep with lambs. As it is written in the Book of Isaiah 2:4 and 11:6-9:


They shall beat their swords into plowshares and their spears into pruning hooks; the nation will not lift sword against nation and they will no longer study warfare.[34]


The wolf will live with the lamb, the leopard will lie down with the goat, the calf and the lion and the yearling together; and a little child will lead them. The cow will feed with the bear, their young will lie down together, and the lion will eat straw like the ox. The infant will play near the hole of the cobra, and the young child put his hand into the viper's nest. They will neither harm nor destroy on all my holy mountain, for the earth will be full of the knowledge of the Lord as the waters cover the sea.[35]

This last metaphor from Tanakh (Hebrew bible) symbolizes the peace that a longed-for messianic age will be characterized by, a peace where natural enemies, the strong and the weak, predator and prey, will live in harmony.

Jews pray for the messianic age of peace every day in the Shmoneh Esreh in addition to faith in the coming of the messianic age constituting one of the thirteen core principles of faith in Judaism, according to Maimonides.
Ideological beliefs
Pacifism
Main article: Pacifism

A peace sign, which is widely associated with pacifism

Pacifism is the categorical opposition to the behaviors of war or violence as a means of settling disputes or of gaining an advantage. Pacifism covers a spectrum of views ranging from the belief that international disputes can and should all be resolved via peaceful behaviors; to calls for the abolition of various organizations which tend to institutionalize aggressive behaviors, such as the military, or arms manufacturers; to opposition to any organization of society that might rely in any way upon governmental force. Such groups which sometimes oppose the governmental use of force include anarchists and libertarians. Absolute pacifism opposes violent behavior under all circumstances, including defense of self and others.

Pacifism may be based on moral principles (a deontological view) or pragmatism (a consequentialist view). Principled pacifism holds that all forms of violent behavior are inappropriate responses to conflict, and are morally wrong. Pragmatic pacifism holds that the costs of war and interpersonal violence are so substantial that better ways of resolving disputes must be found.
Inner peace, meditation, and prayerfulness[edit]

Buddhist monk during meditation near Phu Soidao Nationalpark.
Main article: Inner peace

Psychological or inner peace (i.e. peace of mind) refers to a state of being internally or spiritually at peace, with sufficient knowledge and understanding to keep oneself calm in the face of apparent discord or stress. Being internally "at peace" is considered by many to be a healthy mental state, or homeostasis and to be the opposite of feeling stressful, mentally anxious, or emotionally unstable. Within the meditative traditions, the psychological or inward achievement of "peace of mind" is often associated with bliss and happiness.

Peace of mind, serenity, and calmness are descriptions of a disposition free from the effects of stress. In some meditative traditions, inner peace is believed to be a state of consciousness or enlightenment that may be cultivated by various types of meditation, prayer, t'ai chi ch'uan (太极拳, tàijíquán), yoga, or other various types of mental or physical disciplines. Many such practices refer to this peace as an experience of knowing oneself. An emphasis on finding one's inner peace is often associated with traditions such as Buddhism, Hinduism, and some traditional Christian contemplative practices such as monasticism,[36] as well as with the New Age movement.
Non-Aggression Principle

The Non-Aggression Principle (NAP) asserts that aggression against an individual or an individual's property is always an immoral violation of one's life, liberty, and property rights.[37][38] Utilizing deceit instead of consent to achieve ends is also a violation of the Non-Aggression Principle. Therefore, under the framework of the Non-Aggression principle, rape, murder, deception, involuntary taxation, government regulation, and other behaviors that initiate aggression against otherwise peaceful individuals are considered violations of this principle.[39] This principle is most commonly adhered to by libertarians. A common elevator pitch for this principle is, "Good ideas don't require force."[40]
Satyagraha

Martin Luther King Jr., president of the Southern Christian Leadership Conference, and Mathew Ahmann, executive director of the National Catholic Conference for Interrracial Justice, at a civil rights march on Washington, D.C.
Main article: Satyagraha

Satyagraha is a philosophy and practice of nonviolent resistance developed by Mohandas Karamchand Gandhi. He deployed satyagraha techniques in campaigns for Indian independence and also during his earlier struggles in South Africa.

The word satyagraha itself was coined through a public contest that Gandhi sponsored through the newspaper he published in South Africa, Indian Opinion when he realized that neither the common, contemporary Hindu language nor the English language contained a word that fully expressed his own meanings and intentions when he talked about his nonviolent approaches to conflict. According to Gandhi's autobiography, the contest winner was Maganlal Gandhi (presumably no relation), who submitted the entry 'satyagraha', which Gandhi then modified to 'satyagraha'. Etymologically, this Hindi word means 'truth-firmness', and is commonly translated as 'steadfastness in the truth' or 'truth-force'.

Satyagraha's theory also influenced Martin Luther King Jr., James Bevel, and others during the campaigns they led during the civil rights movement in the United States. The theory of satyagraha sees means and ends as inseparable. Therefore, it is contradictory to try to use violence to obtain peace. As Gandhi wrote: "They say, 'means are, after all, means'. I would say, 'means are, after all, everything'. As the means so the end..."[41] A quote sometimes attributed to Gandhi, but also to A. J. Muste, sums it up: "There is no way to peace; peace is the way".
Monuments[edit]

The following are peace monuments:
NameLocationOrganizationMeaningImage
Japanese Peace Bell New York City, NY United Nations World peace
Fountain of Time Chicago, IL Chicago Park District 100 years of peace between the US and the UK
Fredensborg Palace Fredensborg, Denmark Frederick IV The peace between Denmark–Norway, and Sweden, after the Great Northern ich was signed ned 3 July 1720 on the site of the unfinished palace.
International Peace Garden North Dakota, Manitoba non-profit organization Peace between the US and Canada, World peace
Peace Arch is the border between US and Canada, near Surrey, British Columbia. non-profit organization Built to honor the first 100 years of peace between Great Britain and the United States resulting from the signing of the Treaty of Ghent in 1814.
Statue of Europe Brussels European Commission Unity in Peace in Europe
Waterton-Glacier International Peace Park Alberta, Montana non-profit organization World Peace
Japanese Garden of Peace Fredericksburg, Texas National Museum of the Pacific War A gift from the people of Japan to the people of the United States was presented to honor Chester W. Nimitz and created as a respite from the intensity of violence, destruction, and loss.
Shanti Stupa Pokhara, Nepal Nipponzan-Myōhōji-Daisanga One of eighty peace pagodas in the World.

Theories
See also: Peace and conflict studies § Conceptions of peace

Many different theories of "peace" exist in the world of peace studies, which involve the study of de-escalation, conflict transformation, disarmament, and cessation of violence.[42] The definition of "peace" can vary with religion, culture, or subject of study.
Balance of power
Main article: Balance of power (international relations)

The classical "realist" position is that the key to promoting order between states, and so of increasing the chances of peace, is the maintenance of a balance of power between states – a situation where no state is so dominant that it can "lay down the law to the rest". Exponents of this view have included Metternich, Bismarck, Hans Morgenthau, and Henry Kissinger. A related approach – more in the tradition of Hugo Grotius than Thomas Hobbes – was articulated by the so-called "English school of international relations theory" such as Martin Wight in his book Power Politics (1946, 1978) and Hedley Bull in The Anarchical Society (1977).

As the maintenance of a balance of power could in some circumstances require a willingness to go to war, some critics saw the idea of a balance of power as promoting war rather than promoting peace. This was a radical critique of those supporters of the Allied and Associated Powers who justified entry into World War I because it was necessary to preserve the balance of power in Europe from a German bid for hegemony.

In the second half of the 20th century, and especially during the cold war, a particular form of balance of power – mutual nuclear deterrence – emerged as a widely held doctrine on the key to peace between the great powers. Critics argued that the development of nuclear stockpiles increased the chances of war rather than peace and that the "nuclear umbrella" made it "safe" for smaller wars (e.g. the Vietnam War and the Soviet invasion of Czechoslovakia to end the Prague Spring), so making such wars more likely.
Free trade and interdependence
Main articles: Doux commerce and Peace economics

It was a central tenet of classical liberalism, for example among English liberal thinkers of the late 19th and early 20th century, that free trade promoted peace. For example, the Cambridge economist John Maynard Keynes (1883–1946) said that he was "brought up" on this idea and held it unquestioned until at least the 1920s.[43] During the economic globalization in the decades leading up to World War I, writers such as Norman Angell argued that the growth of economic interdependence between the great powers made war between them futile and therefore unlikely. He made this argument in 1913. A year later Europe's economically interconnected states were embroiled in what would later become known as the First World War.[44]
Democratic peace theory
Main article: Democratic peace theory

The democratic peace theory posits that democracy causes peace because of the accountability, institutions, values, and norms of democratic countries.[45]
Territorial peace theory
Main article: Territorial peace theory

The territorial peace theory posits that peace causes democracy because territorial wars between neighboring countries lead to authoritarian attitudes and disregard for democratic values.[46][47] This theory is supported by historical studies showing that countries rarely become democratic until after their borders have been settled by territorial peace with neighboring countries.[48][49]
War game
Main article: Peace war game

The Peace and War Game is an approach in game theory to understand the relationship between peace and conflicts.

The iterated game hypotheses were originally used by academic groups and computer simulations to study possible strategies of cooperation and aggression.[50]

As peacemakers became richer over time, it became clear that making war had greater costs than initially anticipated. One of the well-studied strategies that acquired wealth more rapidly was based on Genghis Khan, i.e. a constant aggressor making war continually to gain resources. This led, in contrast, to the development of what's known as the "provokable nice guy strategy", a peace-maker until attacked, improved upon merely to win by occasional forgiveness even when attacked. By adding the results of all pairwise games for each player, one sees that multiple players gain wealth cooperating with each other while bleeding a constantly aggressive player.[51]
Socialism and managed capitalism

Socialist, communist, and left-wing liberal writers of the 19th and 20th centuries (e.g., Lenin, J.A. Hobson, John Strachey) argued that capitaliscausehe war (e.g. by promoting imperial or other economic rivalries that lead to international conflict). This led some to argue that international socialism was the key to peace.

However, in response to such writers in the 1930s who argued that capitalism caused the war, the economist John Maynard Keynes (1883–1946) argued that managed capitalism could promote peace. This involved international coordination of fiscal/monetary policies, an international monetary system that did not put the interests of countries against each other, and a high degree of freedom of trade. These ideas underlay Keynes's work during World War II led to the creation of the International Monetary Fund and the World Bank at Bretton Woods in 1944, and later of the General Agreement on Tariffs and Trade (subsequently the World Trade Organization).[52]
International organization and law

One of the most influential theories of peace, especially since Woodrow Wilson led the creation of the League of Nations at the Paris Peace Conference of 1919, is that peace will be advanced if the intentional anarchy of states is replaced through the growth of international law promoted and enforced through international organizations such as the League of Nations, the United Nations, and other functional international organizations. One of the most important early exponents of this view was Alfred Eckhart Zimmern, for example in his 1936 book The League of Nations and the Rule of Law.[53]
Trans-national solidarity

Many "idealist" thinkers about international relations – e.g. in the traditions of Kant and Karl Marx – have argued that the key to peace is the growth of some form of solidarity between peoples (or classes of people) spanning the lines of cleavage between nations or states that lead to war.[54]

One version of this is the idea of promoting international understanding between nations through the international mobility of students – an idea most powerfully advanced by Cecil Rhodes in the creation of the Rhodes Scholarships, and his successors such as J. William Fulbright.[55]

Another theory is that peace can be developed among countries based on the active management of water resources.[56]
Day

Peace day was founded as a day to recognize, honor, and promote peace. It is commemorated each year by United Nations members.
Studies, rankings, and periods
Peace and conflict studies

Detail from Peace and Prosperity (1896), Elihu Vedder, Library of Congress Thomas Jefferson Building, Washington, D.C.
Main article: Peace and conflict studies

Peace and conflict studies is an academic field that identifies and analyses violent and nonviolent behaviors, as well as the structural mechanisms attending violent and non-violent social conflicts. This is to better understand the processes leading to a more desirable human condition.[57] One variation, Peace studies (irenology), is an interdisciplinary effort aiming at the prevention, de-escalation, and solution of conflicts. This contrasts with war studies (polemology), directed at the efficient attainment of victory in conflicts. Disciplines involved may include political science, geography, economics, psychology, sociology, international relations, history, anthropology, religious studies, and gender studies, as well as a variety of other disciplines.
Measurement and ranking

Although peace is widely perceived as something intangible, various organizations have been making efforts to quantify and measure it. The Global Peace Index produced by the Institute for Economics and Peace is a known effort to evaluate peacefulness in countries based on 23 indicators of the absence of violence and the absence of fear of violence.[58]

The last edition of the Index ranks 163 countries on their internal and external levels of peace.[59] According to the 2017 Global Peace Index, Iceland is the most peaceful country in the world while Syria is the least peaceful one.[60] Fragile States Index (formerly known as the Failed States Index) created by the Fund for Peace focuses on the risk of instability or violence in 178 nations. This index measures how fragile a state is by 12 indicators and sub-indicators that evaluate aspects of politics, social economy, and military facets in countries.[61] 2015 Failed State Index reports that the most fragile nation is South Sudan and the least fragile one is Finland.[62] The University of Maryland publishes the Peace and Conflict Instability Ledger to measure peace. It grades 163 countries with 5 indicators and pays the most attention to the risk of political instability or armed conflict over three years. The most recent ledger shows that the most peaceful country is Slovenia on contrary Afghanistan is the most conflicted nation. Besides indicated above reports from the Institute for Economics and Peace, Fund for Peace, and the University of Maryland, other organizations including George Mason University release indexes that rank countries in terms of peacefulness.
Long periods



The longest continuous period of peace and neutrality among currently existing states is observed in Sweden since 1814 and in Switzerland, which has had an official policy of neutrality since 1815. This was made possible partly by the periods of relative peace in Europe and the world known as Pax Britannica (1815–1914), Pax Europaea/Pax Americana (since the 1950s), and Pax Atomica (also since the 1950s).

Other examples of long periods of peace are: the isolationistic Edo period (also known as Tokugawa shogunate) in Japan from 1603 to 1868 (265 years)
Pax Khazarica in Khazar Khanate (south-east Turkey) about 700–950 AD (250 years)
Pax Romana in the Roman empire (for 190 or 206 years