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16.2: War

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  • Learning Objectives

    1. Explain why war is best understood as a social phenomenon and why nations go to war.
    2. Outline both sides to the debate over the size of the US military budget.
    3. List the types of problems that military veterans often face.

    War is “sustained armed conflict” that causes “large-scale loss of life or extreme material destruction” (Worrell, 2011, p. 1). Wars occur both between nations and within nations, when two or more factions engage in armed conflict. War between nations is called international war, while war within nations is called civil war.

    The World at War

    More than 100 million soldiers and civilians are estimated to have died during the international and civil wars of the twentieth century (Leitenberg, 2006). Although this is almost an unimaginable number, there is cause for some hope, even as there is also cause for despair.

    The hope arises from historical evidence that the number of international wars, civil wars, and other types of armed conflict has in fact declined over the centuries, with the number in the past half-century much smaller than in centuries past (Pinker, 2012). Reflecting this decline, a smaller percentage of the world’s population died in armed conflict during the past century than in earlier eras.

    To illustrate this trend, compare two periods of history (Pinker, 2012). The first is the thirteenth century, when the Mongol Empire under the initial leadership of Genghis Khan became an empire in Asia and Eastern Europe through wars and conquest in which it killed 40 million people. The second period is 1939–1945, when World War II killed 55 million people. Although 55 million is more than 40 million, the world’s population in the thirteenth century was only one-seventh its population during the World War II period. A quick calculation shows that about 11 percent of the world’s population died from the Mongolian wars, while 2 percent died from World War II. In terms of the risk of dying in war, then, the Mongolian wars were five times more deadly than World War II.


    Although World War II killed an estimated 55 million people, a smaller percentage of the world’s population died in armed conflict during the twentieth century than in earlier eras.

    Reid Kasprowicz – A Flag for the Fallen – CC BY-NC-ND 2.0.

    Looking further back in world history, the death rate in prehistoric times from tribal warfare was extremely high. If this high rate had held true during the twentieth century, 2 billion people would have died in twentieth-century wars rather than the 100 million who did die (Pinker, 2012). Although wars, other armed conflicts, terrorism, and genocide certainly continue, and 100 million is a terribly high number of deaths, the world overall is in fact more peaceful now than in the past.

    That is the good news and the cause for hope. The cause for despair is twofold. First, war, terrorism, genocide, and other armed conflicts do continue. Even if they are less frequent and less deadly than in the past, that is of little comfort to the tens of millions of people around the world during the past century who died or otherwise suffered in war and other armed conflict and who live in fear today of becoming a victim of armed conflict.

    Second, the world today is a much more dangerous place than in the past because of the existence of nuclear weapons. The thirteenth-century Mongolians killed their 40 million with battleaxes and other crude weapons; the World War II deaths resulted from gunfire and conventional bombs. At the end of that war, however, the nuclear age began when the United States dropped two atomic weapons on Japan that killed tens of thousands instantly and tens of thousands more from radiation exposure.

    Those two weapons were tiny in both number and size compared to nuclear weapons today. More than 20,000 nuclear warheads now exist; 4,800 are operational and almost 2,000 (held by the United States and Russia) are on high alert, ready to be used at any time (Federation of American Scientists, 2011). Each of these warheads is an average of at least twenty times more powerful than each of the atomic bombs that decimated Japan. The Union of Concerned Scientists (2009) summarizes their danger bluntly: “Nuclear weapons remain the greatest and most immediate threat to human civilization.” However more peaceful the world is today, it could easily end at any moment.

    The United States at War

    If we say the history of the United States has been written in war, that is not too much of an exaggeration. The United States, of course, began with the colonial war against England. The American Civil War, also called the War Between the States, then tore it apart less than a century later. Between 1861 and 1865, at least 618,000 and perhaps as many as 750,000 soldiers in both the Union and the Confederacy died on the battlefield or from disease. The minimum estimate almost matches the number of American deaths in all the other wars the United States has fought, and the maximum estimate greatly exceeds this number (see Table 16.2 “US Participation in Major Wars”).

    Table 16.2 US Participation in Major Wars

    War Number of troops Troop deaths Troops wounded
    Revolutionary War 184,000–250,000 4,435 6,188
    War of 1812 286,730 2,260 4,505
    Mexican War 78,218 13,283 4,152
    Civil War 3,867,500 618,222–750,000 412,175
    Spanish-American War 306,760 2,446 1,662
    World War I 4,734,991 116,516 204,002
    World War II 16,112,566 405,399 671,846
    Korean War 5,720,000 36,574 103,284
    Vietnam War 8,744,000 58,209 153,303
    Persian Gulf War 2,225,000 382 467
    Iraq and Afghanistan Wars 2,333,972 6,251 47,566
    Note: Deaths are from combat, disease, and other causes.

    Sources: Fischer, H. (2005). American war and military operations casualties: Lists and statistics. Retrieved from;; Hacker, J. D. (2011, September 20). New York Times. Retrieved from; US Department of Defense. (2012, May 18). Operation Iraqi Freedom (OIF), Operation New Dawn (OND), and Operation Enduring Freedom (OEF) U.S. Casualty Status. Retrieved from (accessed February 16, 2012); Martinez, L. (2011, November 11). US veterans: By the numbers. ABC News. Retrieved from

    The United States has been at war in one-fifth of the years it has existed (Bumiller, 2010). Between the end of the colonial period and 1993, the US military was involved in at least 234 declared wars, undeclared wars, or other situations abroad involving actual or potential armed conflict (Collier, 1993). Since 1993, US armed forces have waged war in Iraq and in Afghanistan and also joined international military operations in such countries as Bosnia, Herzegovina, and Libya. By any measure, then, the US military has played a fundamental role, for better or worse, in the nation’s foreign affairs historically and also today. Supporters of this role say the military has both protected and advanced the political and economic interests of the United States, while critics, as we have seen, charge that the military has been an instrument of imperialism.

    Explaining War

    The enormity of war has long stimulated scholarly interest in why humans wage war (Levy & Thompson, 2010). A popular explanation for war derives from evolutionary biology. According to this argument, war is part of our genetic heritage because the humans who survived tens of thousands of years ago were those who were most able, by virtue of their temperament and physicality, to take needed resources from other humans they attacked and to defend themselves from attackers. In this manner, a genetic tendency for physical aggression and warfare developed and thus still exists today. In support of this evolutionary argument, some scientists note that chimpanzees and other primates also engage in group aggression against others of their species (Wrangham, 2004).

    However, other scientists dispute the evolutionary explanation for several reasons (Begley, 2009). First, the human brain is far more advanced than the brains of other primates, and genetic instincts that might drive these primates’ behavior do not necessarily drive human behavior. Second, many societies studied by anthropologists have been very peaceful, suggesting that a tendency to warfare is more cultural than biological. Third, most people are not violent, and most soldiers have to be resocialized (in boot camp or its equivalent) to overcome their deep moral convictions against killing. If warlike tendencies were part of human genetic heritage, these convictions would not exist.


    Scholars have attempted to explain why human beings wage war. A popular explanation comes from the field of evolutionary biology and claims that a tendency toward warfare is hardwired into our genetic heritage because it conferred certain evolutionary advantages.

    Image courtesy of Sgt. Joshua Risner, US Army, BAGHDAD_-_Iraqi_Soldiers,_with_the_6th_IA_Division,_ familiarize_themselves_with_their_targets_and_prepare_ for_a_PKC_machine_gun_range_at_Combat _Outpost_402,_here,_Sept._28._In_addition_to_ marksmanship.jpg.

    War as a Social Phenomenon

    If warfare is not biological in origin, then it is best understood as a social phenomenon, one that has its roots in the decisions of political and military officials. Sometimes, as with the US entrance into World War II after Pearl Harbor, these decisions are sincere and based on a perceived necessity to defend a nation’s people and resources, and sometimes these decisions are based on cynicism and deceit (Solomon, 2006).

    A prime example of this latter dynamic is the Vietnam War. The 1964 Gulf of Tonkin Resolution, in which Congress authorized President Lyndon Johnson to wage an undeclared war in Vietnam, was passed after North Vietnamese torpedo boats allegedly attacked US ships. However, later investigation revealed that the attack never occurred and that the White House lied to Congress and the American people (Wells, 1994). Four decades later, questions of deceit were again raised after the United States began the war against Iraq because of its alleged possession of weapons of mass destruction. These weapons were never found, and critics charged that the White House had fabricated and exaggerated evidence of the weapons in order to win public and congressional support for the war (Danner, 2006).

    Population Change and Environmental Change

    Although war is a social phenomenon arising from decisions of political and military officials, other phenomena can make it more likely that these officials will decide to go to war. These more basic causes of war include population change and environmental change. As Chapter 15 “Population and the Environment” discussed, population growth may lead to armed conflict of various types, including war, because growing populations need more food, water, and other resources. History shows that when these resources become too scarce within a society, that society is more likely to go to war to wrest these resources from another society (Gleditsch & Theisen, 2010).

    Chapter 15 “Population and the Environment” also discussed environmental change as a source of armed conflict, including war (Fisman & Miguel, 2010). Recall that when weather disasters and other environmental changes cause drought and other problems, crops and other resources become scarcer. Historically, this scarcity has again motivated societies to go to war.

    Ideology and Prejudice

    Nations also go to war for ideological reasons: they have certain belief systems that lead them to hold prejudice and other hostile feelings toward nations with different belief systems. Religion is a very important ideology in this regard. Historically and also today, nations in the Middle East and elsewhere have gone to war or are otherwise in conflict because of religious differences. Although the causes of World War II are complex, Hitler’s effort to conquer much of Europe stemmed at least partly from his belief that Aryans (Germans and other Europeans with blond hair and blue eyes) were a superior species and non-Aryans were an inferior species (Bess, 2008).