War is reciprocated armed conflict between political units aimed at a desired political end-state.
In his book, On War, Prussian military theoretician Carl Von Clausewitz calls war the "continuation of political intercourse, carried on with other means." War is an interaction in which two or more militaries have a “struggle of wills”.
A civil war is a dispute between parties within the same nation. War is not considered to be the same as occupation, murder, or genocide because of the reciprocal nature of the violent struggle, and the organized nature of the units involved. War is also a cultural entity, and its practice is not linked to any single type of political organization or society. Rather, as discussed by John Keegan in his “History Of Warfare”, war is a universal phenomenon whose form and scope is defined by the society that wages it.  The conduct of war extends along a continuum, from the almost universal tribal warfare that began well before recorded human history, to wars between city states, nations, or empires.
A group of combatants and their support is called an army on land, a navy at sea, and an air force in the air. Wars may be conducted simultaneously in one or more different theatres. Within each theatre, there may be one or more consecutive military campaigns.
A military campaign includes not only fighting but also intelligence, troop movements, supplies, propaganda, and other components. A period of continuous conflict is traditionally called a battle, although this terminology is not always applied to conflicts involving aircraft, missiles or bombs alone, in the absence of ground troops or naval forces.
War is not limited to the human species, as ants engage in massive inter-species conflicts which might be termed warfare. It is theorized that other species also engage in similar behavior, although this is not well documented.   
See main article: History of war. Before the dawn of civilization, war likely consisted of small-scale raiding. One half of the people found in a Nubian cemetery dating to as early as 12,000 years ago had died of violence. Since the rise of the state some 5,000 years ago, military activity has occurred over much of the globe. The advent of gunpowder and the acceleration of technological advances led to modern warfare.
The Human Security Report 2005 documented a significant decline in the number and severity of armed conflicts since the end of the Cold War in the early 1990s. However, the evidence examined in the 2008 edition of the Center for International Development and Conflict Management's Peace and Conflict study indicated that the overall decline in conflicts had stalled.
Motivations for war may be different for those ordering the war than for those undertaking the war. For a state to prosecute a war it must have the support of its leadership, its military forces, and the population. For example, in the Third Punic War, Rome's leaders may have wished to make war with Carthage for the purpose of eliminating a resurgent rival, while the individual soldiers may have been motivated by a wish to make money. Since many people are involved, a war may acquire a life of its own from the confluence of many different motivations.
In Why Nations Go to War, by John G. Stoessinger, the author points out that both sides will claim that morality justifies their fight. He also states that the rationale for beginning a war depends on an overly optimistic assessment of the outcome of hostilities (casualties and costs), and on misperceptions of the enemy's intentions. In War Before Civilization, Lawrence H. Keeley, a professor at the University of Illinois, says that approximately 90–95% of known societies throughout history engaged in at least occasional warfare, and many fought constantly.
In Western Europe, since the late 18th century, more than 150 conflicts and about 600 battles had taken place.
Wars happen when a group of people or an organization perceives the benefits that can be obtained to be greater than the cost. This can happen for a variety of reasons:
It can be ended by eleminitating all of the enemies
Psychologists such as E.F.M. Durban and John Bowlby have argued that human beings are inherently violent. While this violence is repressed in normal society, it needs the occasional outlet provided by war. This mixes with other notions such as displacement, where a person transfers their grievances into bias and hatred against other ethnic groups, racial groups, religions, nations or ideologies.
While these theories may have some explanatory value about why wars occur, they do not explain when or how they occur. Nor do they explain the existence of certain human cultures completely devoid of war. If the innate psychology of the human mind is unchanging, these variations are inconsistent. A solution adapted to this problem by militarists such as Franz Alexander is that peace does not really exist. Periods that are seen as peaceful are actually periods of preparation for a later war or when war is suppressed by a state of great power, such as the Pax Britannica.
If war is innate to human nature, as is presupposed and predetermined (according to determinism philosophy) by many psychological theories, then there is little hope of ever escaping it. Psychologists have argued that while human temperament allows wars to occur, this only happens when mentally unbalanced people are in control of a nation. This school of thought argues leaders that seek war such as Napoleon, Hitler, Saddam Hussein, and Stalin were mentally abnormal, but fails to explain the millions of free and presumably sane people who wage wars at their behest.
Some psychologists argue that such leaders are a manifestation of the build up of anger and madness repressed in modern societies and it is only they that are allowed to show various mental anomalies. Because people elect and support such leaders suggestions have been made that very few people are in fact sane and that modern society is an unhealthy one.
The Italian psychoanalyst Franco Fornari, a follower of Melanie Klein, thought that war was the paranoid or projective “elaboration” of mourning. (Fornari 1975). Our nation and country play an unconscious maternal role in our feelings, as expressed in the term “motherland.” Fornari thought that war and violence develop out of our “love need”: our wish to preserve and defend the sacred object to which we are attached, namely our early mother and our fusion with her. For the adult, nations are the sacred objects that generate warfare. Fornari focused upon sacrifice as the essence of war: the astonishing willingness of human beings to die for their country, to give over their bodies to their nation. Fornari called war the “spectacular establishment of a general human situation whereby death assumes absolute value.” We are sure that the ideas for which we die must be true, because “death becomes a demonstrative process.” It is argued that national leaders take the role of fathers and people taken the role of children.
A distinct branch of the psychological theories of war are the arguments based on evolutionary psychology. This school tends to see war as an extension of animal behaviour, such as territoriality and competition. However, while war has a natural cause, the development of technology has accelerated human destructiveness to a level that is irrational and damaging to the species. The earliest advocate of this theory was Konrad Lorenz.
These theories have been criticized by scholars such as John G. Kennedy, who argue that the organized, sustained war of humans differs more than just technologically from the territorial fights between animals. Ashley Montagu strongly denies such universalistic instinctual arguments, pointing out that social factors and childhood socialization are important in determining the nature and presence of warfare. Thus while human aggression may be a universal occurrence, warfare is not and would appear to have been a historical invention, associated with certain types of human societies.
Sociology has long been very concerned with the origins of war, and many thousands of theories have been advanced, many of them contradictory. Sociology has thus divided into a number of schools. One, the Primat der Innenpolitik (Primacy of Domestic Politics) school based on the works of Eckart Kehr and Hans-Ulrich Wehler, sees war as the product of domestic conditions, with only the target of aggression being determined by international realities. Thus World War I was not a product of international disputes, secret treaties, or the balance of power but a product of the economic, social, and political situation within each of the states involved.
This differs from the traditional Primat der Außenpolitik (Primacy of Foreign Politics) approach of Carl von Clausewitz and Leopold von Ranke that argues it is the decisions of statesmen and the geopolitical situation that leads to peace.
Demographic theories can be grouped into two classes, Malthusian theories and youth bulge theories.
Malthusian theories see expanding population and scarce resources as a source of violent conflict.
Pope Urban II in 1095, on the eve of the First Crusade, wrote, "For this land which you now inhabit, shut in on all sides by the sea and the mountain peaks, is too narrow for your large population; it scarcely furnishes food enough for its cultivators. Hence it is that you murder and devour one another, that you wage wars, and that many among you perish in civil strife. Let hatred, therefore, depart from among you; let your quarrels end. Enter upon the road to the Holy Sepulchre; wrest that land from a wicked race, and subject it to yourselves."
This is one of the earliest expressions of what has come to be called the Malthusian theory of war, in which wars are caused by expanding populations and limited resources. Thomas Malthus (1766 - 1834) wrote that populations always increase until they are limited by war, disease, or famine.
This theory is thought by Malthusians to account for the relative decrease in wars during the past fifty years, especially in the developed world, where advances in agriculture have made it possible to support a much larger population than was formerly the case, and where birth control has dramatically slowed the increase in population.
Youth bulge theory differs significantly from malthusian theories. Its adherents see a combination of large male youth cohorts (as graphically represented as a "youth bulge" in a population pyramid) with a lack of regular, peaceful employment opportunities as a risk pool for violence. While malthusian theories focus on a disparity between a growing population and available natural resources, youth bulge theory focuses on a disparity between non-inheriting, "excess" young males and available social positions within the existing social system of division of labour.
Contributors to the development of youth bulge theory include French sociologist Gaston Bouthoul,, U.S. sociologist Jack A. Goldstone,, U.S. political scientist Gary Fuller,,   and German sociologist Gunnar Heinsohn. Samuel Huntington has modified his Clash of Civilizations theory by using youth bulge theory as its foundation:
I don't think Islam is any more violent than any other religions, and I suspect if you added it all up, more people have been slaughtered by Christians over the centuries than by Muslims. But the key factor is the demographic factor. Generally speaking, the people who go out and kill other people are males between the ages of 16 and 30.
During the 1960s, 70s and 80s there were high birth rates in the Muslim world, and this has given rise to a huge youth bulge. But the bulge will fade. Muslim birth rates are going down; in fact, they have dropped dramatically in some countries. Islam did spread by the sword originally, but I don't think there is anything inherently violent in Muslim theology."
Youth Bulge theories represent a relatively recent development but seem to have become more influential in guiding U.S. foreign policy and military strategy as both Goldstone and Fuller have acted as consultants to the U.S. Government. CIA Inspector General John L. Helgerson referred to youth bulge theory in his 2002 report "The National Security Implications of Global Demographic Change".
According to Heinsohn, who has proposed youth bulge theory in its most generalized form, a youth bulge occurs when 30 to 40 percent of the males of a nation belong to the "fighting age" cohorts from 15 to 29 years of age. It will follow periods with total fertility rates as high as 4-8 children per woman with a 15-29 year delay.
A total fertility rate of 2.1 children born by a woman during her lifetime represents a situation of in which the son will replace the father, and the daughter will replace the mother. Thus, a total fertility rate of 2.1 represents replacement level, while anything below represents a sub-replacement fertility rate leading to population decline.
Total fertility rates above 2.1 will lead to population growth and to a youth bulge. A total fertility rate of 4-8 children per mother implies 2-4 sons per mother. Consequently, one father has to leave not 1, but 2 to 4 social positions (jobs) to give all his sons a perspective for life, which is usually hard to achieve. Since respectable positions cannot be increased at the same speed as food, textbooks and vaccines, many "angry young men" find themselves in a situation that tends to escalate their adolescent anger into violence: they are
The combination of these stress factors according to Heinsohn usually heads for one of six different exits:
Religions and ideologies are seen as secondary factors that are being used to legitimate violence, but will not lead to violence by themselves if no youth bulge is present. Consequently, youth bulge theorists see both past "Christianist" European colonialism and imperialism and today's "Islamist" civil unrest and terrorism as results of high birth rates producing youth bulges.
While during the period of European colonialism, European countries had high birthrates and huge youth bulges that fueled colonialist expansion, today Afghanistan, which has a total fertility rate of 6 children per woman and an estimated unemployment rate of 40%, would represent a typical youth bulge country. The Gaza Strip can be seen as another example of youth-bulge-driven violence, especially if compared to Lebanon which is geographically close, yet remarkably more peaceful.
Among prominent historical events that have been linked to the existence of youth bulges is the role played by the historically large youth cohorts in the rebellion and revolution waves of early modern Europe, including French Revolution of 1789, and the importance of economic depression hitting the largest German youth cohorts ever in explaining the rise of Nazism in Germany in the 1930s. The 1994 Rwandan Genocide has also been analyzed as following a massive youth bulge.
While the security implications of rapid population growth have been well known since the completion of the National Security Study Memorandum 200 in 1974, neither the U.S. nor the WHO have effectively implemented the recommended preventive measures to control population growth to avert the terror threat they are now facing. Prominent demographer Stephen D. Mumford attributes this to the influence of the Catholic Church.
Youth Bulge theory has been subjected to statistical analysis by the World Bank, Population Action International, and the Berlin Institute for Population and Development. Detailed demographic data for most countries is available at the international database of the United States Census Bureau.
Youth bulge theories have been criticized as leading to racial, gender and age discrimination.
Rationalist theories of war assume that both sides to a potential war are rational, which is to say that each side wants to get the best possible outcome for itself for the least possible loss of life and property to its own side. Given this assumption, if both countries knew in advance how the war would turn out, it would be better for both of them to just accept the post-war outcome without having to actually pay the costs of fighting the war. This is based on the notion, generally agreed to by almost all scholars of war since Carl von Clausewitz, that wars are reciprocal, that all wars require both a decision to attack and also a decision to resist attack.Rationalist theory offers three reasons why some countries cannot find a bargain and instead resort to war: issue indivisibility, information asymmetry with incentive to deceive, and the inability to make credible commitments.
Issue indivisibility occurs when the two parties cannot avoid war by bargaining because the thing over which they are fighting cannot be shared between them, only owned entirely by one side or the other. Religious issues, such as control over the Temple Mount in Jerusalem, are more likely to be indivisible than economic issues.
A bigger branch of the theory, advanced by scholars of international relations such as Geoffrey Blainey, is that both sides decide to go to war and one side may have miscalculated.
Some go further and say that there is a problem of information asymmetry with incentives to misrepresent. The two countries may not agree on who would win a war between them, or whether victory would be overwhelming or merely eked out, because each side has military secrets about its own capabilities. They will not avoid the bargaining failure by sharing their secrets, since they cannot trust each other not to lie and exaggerate their strength to extract more concessions. For example, Sweden made efforts to deceive Nazi Germany that it would resist an attack fiercely, partly by playing on the myth of Aryan superiority and by making sure that Hermann Göring only saw elite troops in action, often dressed up as regular soldiers, when he came to visit.
The American decision to enter the Vietnam War was made with the full knowledge that the communist forces would resist them, but did not believe that the guerrillas had the capability to long oppose American forces.
Thirdly, bargaining may fail due to the states' inability to make credible commitments. In this scenario, the two countries might be able to come to a bargain that would avert war if they could stick to it, but the benefits of the bargain will make one side more powerful and lead it to demand even more in the future, so that the weaker side has an incentive to make a stand now.
Rationalist explanations of war can be critiqued on a number of grounds. The assumptions of cost-benefit calculations become dubious in the most extreme genocidal cases of World War II, where the only bargain offered in some cases was infinitely bad. Rationalist theories typically assume that the state acts as a unitary individual, doing what is best for the state as a whole; this is problematic when, for example, the country's leader is beholden to a very small number of people, as in a personalistic dictatorship. Rationalist theory also assumes that the actors are rational, able to accurately assess their likelihood of success or failure, but the proponents of the psychological theories above would disagree.
Another school of thought argues that war can be seen as an outgrowth of economic competition in a chaotic and competitive international system. In this view wars begin as a pursuit of new markets, of natural resources, and of wealth. This theory has been applied to many conflicts.
Some to the left of the political spectrum argue such wars serve the interests of the wealthy but are fought by the poor. Sometimes this is referred to as a resource curse. Some to the right of the political spectrum may counter that poverty is relative and one poor in one country can be relatively wealthy in another.
Such counter arguments become less valid as the increasing mobility of capital and information level the distributions of wealth worldwide, or when considering that it is relative, not absolute, wealth differences that may fuel wars. There are those on the extreme right of the political spectrum who provide support, fascists in particular, by asserting a natural right of the strong to whatever the weak cannot hold by force. Some centrist, capitalist, world leaders, including Presidents of the United States and US Generals, expressed support for an economic view of war.
"Is there any man, is there any woman, let me say any child here that does not know that the seed of war in the modern world is industrial and commercial rivalry?" - Woodrow Wilson, September 11, 1919, St. Louis.
"I spent 33 years and four months in active military service and during that period I spent most of my time as a high class muscle man for Big Business, for Wall Street and the bankers. In short, I was a racketeer, a gangster for capitalism." - simultaneously highest ranking and most decorated United States Marine (including two Medals of Honor) Major General Smedley Butler (and a Republican Party primary candidate for the United States Senate) 1935.
"For the corporation executives, the military metaphysic often coincides with their interest in a stable and planned flow of profit; it enables them to have their risk underwritten by public money; it enables them reasonably to expect that they can exploit for private profit now and later, the risky research developments paid for by public money. It is, in brief, a mask of the subsidized capitalism from which they extract profit and upon which their power is based." C. Wright Mills, Causes of world war 3,1960
"In the councils of government, we must guard against the acquisition of unwarranted influence, whether sought or unsought, by the military-industrial complex. The potential for disastrous rise of misplaced power exists and will persist." - Dwight Eisenhower, Farewell Address, Jan. 17, 1961.
The Marxist theory of war argues that all war grows out of the class struggle. It sees wars as imperial ventures to enhance the power of the ruling class and divide the proletariat of the world by pitting them against each other for contrived ideals such as nationalism or religion. Wars are a natural outgrowth of the free market and class system, and will not disappear until a world revolution occurs.
The statistical analysis of war was pioneered by Lewis Fry Richardson following World War I. More recent databases of wars and armed conflict have been assembled by the Correlates of War Project, Peter Brecke and the Uppsala Department of Peace and Conflict Research.
There are several different international relations theory schools. Supporters of realism in international relations argue that the motivation of states is the quest for security, to ensure survival.One position, sometimes argued to contradict the realist view, is that there is much empirical evidence to support the claim that states that are democracies do not go to war with each other, an idea known as the democratic peace theory. Other factors included are difference in moral and religious beliefs, economical and trade disagreements, declaring independence, and others.
Another major theory relating to power in international relations and machtpolitik is the Power Transition theory, which distributes the world into a hierarchy and explains major wars as part of a cycle of hegemons being destabilized by a great power which does not support the hegemons' control.
The biggest war ever seen was World War II with 71,100,000 dead.
Ayn Rand, developer of Objectivism advocates rational individualism and laissez-faire capitalism, adduced that if men want to oppose war, it is statism that they must oppose. She maintained that so long as people hold the tribal notion that the individual is sacrificial fodder for the collective, that some men have the right to rule others by force, and that some (any) alleged "good" can justify it -- there can be no peace within a nation and no peace among nations.
The war to become known as one must entail some degree of confrontation using weapons and other military technology and equipment by armed forces employing military tactics and Operational art within the broad military strategy subject to military logistics. War Studies by military theorists throughout military history have sought to identify the Philosophy of war, and to reduce it to a Military science.
In general modern military science considers several factors before a National defence policy is created to allow a war to commence: the environment in the area(s) of combat operations, the posture national forces will adopt on the commencement of a war, and the type of warfare troops will be engaged in.
Conventional warfare is an attempt to reduce an opponent's military capability through open battle. It is a declared war between existing states in which nuclear, biological, or chemical weapons are not used or only see limited deployment in support of conventional military goals and maneuvers. Nuclear warfare is a war in which nuclear weapons are the primary method of coercing the capitulation of the other side, as opposed to a supporting tactical or strategic role in a conventional conflict. The opposite of conventional warfare, unconventional warfare, is an attempt to achieve military victory through acquiescence, capitulation, or clandestine support for one side of an existing conflict using non-traditional means.
Civil war is a war where the forces in conflict belong to the same nation or political entity and are vying for control of that nation or political entity. Asymmetric warfare is a conflict between two populations of drastically different levels of military mechanization, size or capability. Asymmetric conflicts often result in guerrilla tactics being used to overcome the sometimes vast gaps in technology and force size. Intentional air pollution in combat is one of a collection of techniques collectively called chemical warfare. Poison gas as a chemical weapons was principally used during World War I, and resulted in an estimated 91,198 deaths and 1,205,655 injuries. Various treaties have sought to ban its further use. Non-lethal chemical weapons, such as tear gas and pepper spray, are widely used, sometimes with deadly effect.
|Extortionate||Pecheneg and Cuman forays on Rus in 9th - 13th centuries|
|Aggressive||the wars of Alexander the Great in 326 - 323 BC|
|Imperial Rebellion||Algerian War|
|Dynastic||War of the Spanish Succession|
|Revolutionary||French Revolutionary Wars|
|Civil||Spanish Civil War|
|Secessionist||American Civil War|
|Nuclear||There have been only two uses of nuclear weapons in war, during World War II by the U.S. against Empire of Japan.|
Historian Victor Davis Hanson has claimed there exists a unique "Western Way of War", in an attempt to explain the military successes of Western Europe. It originated in Ancient Greece, where, in an effort to reduce the damage that warfare has on society, the city-states developed the concept of a decisive pitched battle between heavy infantry. This would be preceded by formal declarations of war and followed by peace negotiations. In this system constant low-level skirmishing and guerrilla warfare were phased out in favour of a single, decisive contest, which in the end cost both sides less in casualties and property damage. Although it was later perverted by Alexander the Great, this style of war initially allowed neighbours with limited resources to coexist and prosper.
He argues that Western-style armies are characterised by an emphasis on discipline and teamwork above individual bravado. Examples of Western victories over non-Western armies include the Battle of Marathon, the Battle of Gaugamela, the Siege of Tenochtitlan, and the defence of Rorke's Drift.
The environment in which a war is fought has a significant impact on the type of combat which takes place, and can include within its area different types of terrain. This in turn means that soldiers have to be trained to fight in a specific types of environments and terrains that generally reflects troops' mobility limitations or enablers.These include:Conventional warfare
Many may experience post-traumatic stress disorder by becoming traumatized by the experience of war. They would have dedicated their lives to fighting battles, with little possibility of regaining the ability to live successfully as a civilian. One-tenth of mobilised American men were hospitalised for mental disturbances between 1942 and 1945, and after thirty-five days of uninterrupted combat, 98% of them manifested psychiatric disturbances in varying degrees.
Based on 1860 census figures, 8% of all white males aged 13 to 43 died in the American Civil War, including 6% in the North and 18% in the South. Of the 60 million European soldiers who were mobilized in World War I, 8 million were killed, 7 million were permanently disabled, and 15 million were seriously injured.
Many wars have been accompanied by significant depopulations. During the Thirty Years' War in Europe, for example, the population of the German states was reduced by about 30%. The Swedish armies alone may have destroyed up to 2,000 castles, 18,000 villages and 1,500 towns in Germany, one-third of all German towns.
Estimates for the total casualties of World War II vary, but most suggest that some 60 million people died in the war, including about 20 million soldiers and 40 million civilians. The Soviet Union lost around 27 million people during the war, about half of all World War II casualties. The largest number of civilian deaths in a single city was 1.2 million citizens dead during the 872-day Siege of Leningrad.
Typically speaking, war becomes very intertwined with the economy and many wars are based on economic reasons such as the American Civil War and have in some cases, World War Two for example, brought many nations great prosperity. Most often the cost of war draws funding away from other governmental programs and funding.
The Great Depression ended as nations increased their production of war materials at the start of World War II. The financial cost of the World War II is estimated at about a trillion 1944 U.S. dollars worldwide,  making it the most costly war in capital as well as lives. The property damage in the Soviet Union inflicted by the Axis invasion was estimated to a value of 679 billion rubles. The combined damage consisted of complete or partial destruction of 1,710 cities and towns, 70,000 villages/hamlets, 2,508 church buildings, 31,850 industrial establishments, 40,000 miles of railroad, 4100 railroad stations, 40,000 hospitals, 84,000 schools, and 43,000 public libraries.
Throughout history war has been the source of serious moral questions. Although many ancient nations and some modern ones have viewed war as noble, over the sweep of history, concerns about the morality of war have gradually increased. Today, war is seen by some as undesirable and morally problematic. At the same time, many view war, or at least the preparation and readiness and willingness to engage in war, as necessary for the defense of their country and therefore a just war. Pacifists believe that war is inherently immoral and that no war should ever be fought.
The negative view of war has not always been held as widely as it is today. Heinrich von Treitschke saw war as humanity's highest activity where courage, honour, and ability were more necessary than in any other endeavour. Friedrich Nietzsche also saw war as an opportunity for the Übermensch to display heroism, honour, and other virtues.
Another supporter of war, Georg Wilhelm Friedrich Hegel, favoured it as part of the necessary process required for history to unfold and allow society to progress. At the outbreak of World War I, the writer Thomas Mann wrote, "Is not peace an element of civil corruption and war a purification, a liberation, an enormous hope?" This attitude has been embraced by societies from Sparta and Rome in the ancient world to the fascist states of the 1930s.
International law recognizes only two cases for a legitimate war:
The subset of international law known as the law of war or international humanitarian law also recognises regulations for the conduct of war, including the Geneva Conventions governing the legitimacy of certain kinds of weapons, and the treatment of prisoners of war. Cases where these conventions are broken are considered war crimes, and since the Nuremberg Trials at the end of World War II the international community has established a number of tribunals to try such cases.
A nation's economy is often stimulated by government war-spending. When countries wage war, more weapons, armor, ammunition, and the like are needed to be created and sold to the armies, thus their economies can enter a boom (or war economy) reducing unemployment. One major depression, the Great Depression, was ended because of World War II. However this thinking is challenged by the parable of the broken window which describes this idea as a fallacy.
The political and economic circumstances in the peace that follows war usually depends on the "facts on the ground". Where evenly matched adversaries decide that the conflict has resulted in a stalemate, they may cease hostilities to avoid further loss of life and property. They may decide to restore the antebellum territorial boundaries, redraw boundaries at the line of military control, or negotiate to keep or exchange captured territory. Negotiations between parties involved at the end of a war often result in a treaty, such as the Treaty of Versailles of 1919, which ended the First World War.
A warring party that surrenders or capitulates may have little negotiating power, with the victorious side either imposing a settlement or dictating most of the terms of any treaty. A common result is that conquered territory is brought under the dominion of the stronger military power. An unconditional surrender is made in the face of overwhelming military force as an attempt to prevent further harm to life and property. For example, the Empire of Japan gave an unconditional surrender to the Allies of World War II after the atomic bombings of Hiroshima and Nagasaki (see Surrender of Japan), the preceding massive strategic bombardment of Japan and declaration of war and the immediate invasion of Manchuria by the Soviet Union. A settlement or surrender may also be obtained through deception or bluffing.
Many other wars, however, have ended in complete destruction of the opposing territory, such as the Battle of Carthage of the Third Punic War between the Phoenician city of Carthage and Ancient Rome in 149 BC. In 146 BC the Romans burned the city, enslaved its citizens, and razed the buildings.
Some wars or aggressive actions end when the military objective of the victorious side has been achieved. Others do not, especially in cases where the state structures do not exist, or have collapsed prior to the victory of the conqueror. In such cases, disorganised guerilla warfare may continue for a considerable period. In cases of complete surrender conquered territories may be brought under the permanent dominion of the victorious side. A raid for the purposes of looting may be completed with the successful capture of goods. In other cases an aggressor may decide to end hostilities to avoid continued losses and cease hostilities without obtaining the original objective, such as happened in the Iran–Iraq War.
Some hostilities, such as insurgency or civil war, may persist for long periods of time with only a low level of military activity. In some cases there is no negotiation of any official treaty, but fighting may trail off and eventually stop after the political demands of the belligerent groups have been reconciled, a political settlement has been negotiated, or combatants are gradually killed or decide the conflict is futile.
This is an incomplete list of wars.
PBS on Now: Talking About War How does democracy decide to wage war?