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Military conflicts have been increasing since 1870, study finds

June 30, 2011
Courtesy of the University of Warwick
and World Science staff

Mil­i­tary con­flicts be­tween states have been in­creas­ing in fre­quen­cy from 1870 to 2001—even with­out count­ing the best-known con­flagra­t­ions such as the world wars and Amer­i­can in­ter­ven­tions, a study has found.

The sur­vey of con­flict counted eve­ry­thing from all-out shoot­ing wars and uses of mil­i­tary force to dis­plays of force such as send­ing war­ships and clos­ing bor­ders. This does­n’t meas­ure the in­tens­ity of vi­o­lence, re­search­ers said, but does cap­ture gov­ern­ments’ read­i­ness to set­tle dis­putes by force. Only con­flicts be­tween states, not civ­il wars, were counted.

Iden­ti­fi­able fac­tors be­hind the in­crease—two pe­r­cent more wars each year, on av­er­age—are that there are more bor­ders and weapons are cheape­r, ac­cord­ing to the in­ves­ti­ga­tors. By their count, the to­tal num­ber of na­t­ions rose from 47 in 1870 to 187 on the eve of the World Trade Cen­ter at­tacks.

“There is a close con­nec­tion be­tween wars and the crea­t­ion of states and new bor­ders,” said Mark Har­ri­son of the Un­ivers­ity of War­wick, U.K., one of the re­search­ers. “This is not re­as­sur­ing,” he added. “No mat­ter how you di­vide it, we have only one plan­et… you can nev­er be quite sure what lit­tle con­flicts will not sud­denly snow­ball in­to much wid­er, more deadly strug­gles.”

It may seem the world en­joyed rel­a­tive peace be­tween the Cold War and 9/11, but the study by Har­ri­son and Niko­laus Wolf of Hum­boldt Un­ivers­ity, U.K. found that the num­ber of con­flicts be­tween pairs of states rose steadily from 6 per year on av­er­age be­tween 1870 and 1913 to 17 per year in the pe­riod of the two World Wars, 31 per year in the Cold War, and 36 per year in the 1990s.

“The num­ber of con­flicts has been ris­ing on a sta­ble trend. Be­cause of two world wars, the pat­tern is ob­vi­ously dis­turbed be­tween 1914 and 1945 but re­mark­ably, af­ter 1945 the fre­quen­cy of wars re­sumed its up­ward course on pret­ty much the same path as be­fore 1913,” Har­ri­son said. The find­ings are to ap­pear in the jour­nal Eco­nom­ic His­tory Re­view.

When the re­search­ers dis­cussed their work with col­leagues, they said the most fre­quent ques­tions have been about the ex­tra wars since 1945: “Aren’t these just Amer­i­ca’s wars?” and “Aren’t these just co­a­li­tion wars in which many far flung coun­tries join sym­bol­ic­ally, yet most nev­er fire a shot?” 

“No” is the an­swer to both, they said; if one dis­re­gards “Amer­i­ca’s wars” al­to­geth­er, the ris­ing trend re­mains. Oth­er schol­ars have found that the av­er­age dis­tance be­tween coun­tries at war has fall­en steadily since the 1950s.

The re­search­ers found that na­t­ions with the larg­est economies have tended to make more fre­quent mil­i­tary in­ter­ven­tions, but there has been no in­crease in this ten­den­cy over 130 years. They al­so found there is no ten­den­cy for richer coun­tries, de­fined by gross do­mes­tic prod­uct per head, to make war more of­ten than oth­ers, and again this has not changed over 130 years. In oth­er words, the read­i­ness to em­bark on mil­i­tary ad­ven­tures is scat­tered fairly un­iformly across the glob­al in­come dis­tri­bu­tion.

The in­crease is puz­zling as well as alarm­ing, the re­search­ers said. Con­ven­tion­al wis­dom said this should­n’t be hap­pen­ing. Na­t­ions have be­come richer, more dem­o­crat­ic, and more in­ter­de­pend­ent on the whole. Thinkers of the En­light­en­ment held that these things should gen­er­ally make the world more peace­ful. Much po­lit­i­cal sci­ence is built on the idea that the lead­ers of richer, more dem­o­crat­ic coun­tries have few­er in­cen­tives to make war and are more con­strained from do­ing so.

“We do not think these ide­as are wrong, but they are in­com­plete,” Har­ri­son said. “With­out be­ing cer­tain of the an­swer, we think po­lit­i­cal sci­en­tists have fo­cused too much on pref­er­ences for war (the ‘de­mand side’) and not enough on ca­pa­bil­i­ties (the ‘supply side.’) Ca­pa­bil­i­ties may be the mis­sing fac­tor in the sto­ry… we ar­gue that the same fac­tors that should have de­pressed the in­cen­tives for rulers to choose con­flict are al­so in­creas­ing the ca­pa­city for war. In oth­er words, we are mak­ing war more fre­quently, not be­cause we want to, but be­cause we can.”

Eco­nom­ic growth has made de­struc­tive pow­er cheape­r, not just in ab­so­lute terms but rel­a­tive to civ­ilian goods, the re­search ar­gues. Moreo­ver, the key to mod­ern states’ ac­qui­si­tion of de­struc­tive pow­er has been the abil­ity to tax and bor­row more than ev­er be­fore, and de­moc­ra­cy fos­ters these ca­pa­ci­ties. Final­ly, war dis­rupts trade, but some coun­tries man­age to main­tain strong trade de­spite war and can wage it more ef­fec­tively as a re­sult.

“Un­der pre­s­ent in­terna­t­ional ar­range­ments,” Har­ri­son said, the “deep seated ten­den­cy” to­ward war is “not some­thing that any one coun­try is go­ing to be able to con­trol.”

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Military conflicts between states have been increasing in frequency from 1870 to 2001—even without counting the best-known conflagrations such as the world wars and American interventions, a study has found. The survey of conflict counted everything from all-out shooting wars and uses of military force to displays of force such as sending warships and closing borders. This doesn’t measure the intensity of violence, researchers said, but does capture governments’ readiness to settle disputes by force. Only conflicts between states, not civil wars, were counted. Identifiable factors behind the increase—two percent more wars each year, on average—are that there are more borders and weapons are cheaper, according to the investigators. By their count, the total number of nations rose from 47 in 1870 to 187 on the eve of the World Trade Center attacks. “There is a close connection between wars and the creation of states and new borders,” said Mark Harrison of the University of Warwick, U.K., one of the researchers. “This is not reassuring,” he added. “No matter how you divide it, we have only one planet… you can never be quite sure what little conflicts will not suddenly snowball into much wider, more deadly struggles.” It may seem the world enjoyed relative peace between the Cold War and 9/11, but the study by Harrison and Nikolaus Wolf of Humboldt University, U.K. found that the number of conflicts between pairs of states rose steadily from 6 per year on average between 1870 and 1913 to 17 per year in the period of the two World Wars, 31 per year in the Cold War, and 36 per year in the 1990s. “The number of conflicts has been rising on a stable trend. Because of two world wars, the pattern is obviously disturbed between 1914 and 1945 but remarkably, after 1945 the frequency of wars resumed its upward course on pretty much the same path as before 1913,” Harrison said. When the researchers discussed their work with colleagues, they said the most frequent questions have been about the extra wars since 1945: “Aren’t these just America’s wars?” and “Aren’t these just coalition wars in which many far flung countries join symbolically, yet most never fire a shot?” “No” is the answer to both, they said; if one disregards “America’s wars” altogether, the rising trend remains. Other scholars have found that the average distance between countries at war has fallen steadily since the 1950s. The researchers found that nations with the largest economies have tended to make more frequent military interventions, but there has been no increase in this tendency over 130 years. They also found there is no tendency for richer countries, defined by gross domestic product per head, to make war more often than others, and again this has not changed over 130 years. In other words, the readiness to embark on military adventures is scattered fairly uniformly across the global income distribution. The increase is puzzling as well as alarming, the researchers said. Conventional wisdom said this shouldn’t be happening. Nations have become richer, more democratic, and more interdependent on the whole. Thinkers of the Enlightenment held that these things should generally make the world more peaceful. Much political science is built on the idea that the leaders of richer, more democratic countries have fewer incentives to make war and are more constrained from doing so. “We do not think these ideas are wrong, but they are incomplete,” Harrison said. “Without being certain of the answer, we think political scientists have focused too much on preferences for war (the ‘demand side’) and not enough on capabilities (the ‘supply side.’) Capabilities may be the missing factor in the story… we argue that the same factors that should have depressed the incentives for rulers to choose conflict are also increasing the capacity for war. In other words, we are making war more frequently, not because we want to, but because we can.” Economic growth has made destructive power cheaper, not just in absolute terms but relative to civilian goods, the research argues. Moreover, the key to modern states’ acquisition of destructive power has been the ability to tax and borrow more than ever before, and democracy fosters these capacities. Finally, war disrupts trade, but some countries manage to maintain strong trade despite war and can wage it more effectively as a result. “Under present international arrangements,” Harrison said, the “deep seated tendency” toward war is “not something that any one country is going to be able to control,” Harrison concluded.