Editing Democratic peace theory (section)

==Other explanations==
{{Weasel|date=February 2014}}

===Economic factors===
{{Main|Capitalist peace}}
[[Image:World GDP Capita 1-2003 A.D.png|thumb|right|upright=1.35|World [[GDP]]/capita 1–2003 AD. The increase in the number of democratic nations has occurred at the same time as the increase in economic wealth.]]
The capitalist peace, or capitalist peace theory, posits that according to given criteria for economic development (capitalism), developed economies have not engaged in war with each other, and rarely enter into low-level disputes. These theories have been proposed as an explanation for democratic peace by accounting for both democracy and the peace among democratic nations. The exact nature of the causality depends upon both the proposed variable and the measure of the indicator for the concept used.

A majority of researchers on the determinants of democracy agree that economic development is a primary factor which allows the formation of a stable and healthy democracy.{{sfn|Hegre|2003}}{{sfn|Weede|2004}} Thus, some researchers have argued that economic development also plays a factor in the establishment of peace.

Mousseau argues that a culture of contracting in advanced market-oriented economies may cause both democracy and peace. These studies indicate that democracy, alone, is an unlikely cause of the democratic peace. A low level of market-oriented economic development may hinder development of liberal institutions and values.{{sfn|Mousseau|2000}}{{sfn|Mousseau|2002}}{{sfn|Mousseau|2003}}{{sfn|Mousseau|2005}} Hegre and Souva confirmed these expectations.{{sfn|Hegre|2000}}{{sfn|Souva|2004}} Mousseau finds that democracy is a significant factor only when both democracies have levels of economic development well above the global median. In fact, the poorest 21% of the democracies studied, and the poorest 4–5% of current democracies, are significantly {{em|more}} likely than other kinds of countries to fight each other.{{sfn|Mousseau|2005}} Mousseau, Hegre, and Oneal confirm that if at least one of the democracies involved has a very low level of economic development, democracy is ineffective in preventing war; however, they find that when also controlling for trade, 91% of all the democratic pairs had high enough development for the pacifying effect of democracy to be important during the 1885–1992 period and all in 1992.{{sfn|Mousseau|Hegre|Oneal|2003}} The difference in results of these two studies may be due to sampling: Mousseau's 2005 study observed only neighboring states where poor countries actually can fight each other. In fact, fully 89% of militarized conflicts between less developed countries from 1920 and 2000 were among directly contiguous neighbors.{{sfn|Mousseau|2005|pp=68–69}} He argues that it is not likely that the results can be explained by trade: Because developed states have large economies, they do not have high levels of trade interdependence.{{sfn|Mousseau|2005|loc=p. 70 and footnote 5}}{{sfn|Mousseau|Hegre|Oneal|2003|p=283}} In fact, the correlation of developed democracy with trade interdependence is a scant 0.06 (Pearson's ''r'' – considered substantively no correlation by statisticians.{{sfn|Mousseau|2005|p=77}}){{Synthesis inline|date=January 2021}}

Both [[World War]]s were fought between countries which can be considered economically developed. Mousseau argues that both Germany and Japan – like the USSR during the Cold War and Saudi Arabia today – had state-managed economies and thus lacked his market norms.{{sfn|Mousseau|2002–2003|p=29}} Hegre finds that democracy is correlated with civil peace only for developed countries, and for countries with high levels of literacy. Conversely, the risk of civil war decreases with development only for democratic countries.{{sfn|Hegre|2003}}

Gartzke argues that [[economic freedom]] (a quite different concept from Mousseau's market norms) or financial dependence explains the developed democratic peace, and these countries may be weak on these dimensions too.{{sfn|Gartzke|2005}}{{sfn|Gartzke|2007}}{{sfn|Gwartney|Lawson|Gartzke|2005}} Rummel criticizes Gartzke's methodology and argues that his results are invalid.{{sfn|Rummel|2005}}

Allan Dafoe, John R. Oneal, and Bruce Russett have challenged Gartzke and Mousseau's research.{{sfn|Dafoe|Oneal|Russett|2013}}

Several studies find that democracy, more [[trade]] causing greater economic [[interdependence]], and membership in more [[intergovernmental organizations]] reduce the risk of war. This is often called the Kantian peace theory since it is similar to Kant's earlier theory about a perpetual peace; it is often also called "liberal peace" theory, especially when one focuses on the effects of trade and democracy. (The theory that [[free trade]] can cause peace is quite old and referred to as [[Cobdenism]].) Many researchers agree that these variables positively affect each other but each has a separate pacifying effect. For example, in countries exchanging a substantial amount of trade, economic interest groups may exist that oppose a reciprocal disruptive war, but in democracy such groups may have more power, and the political leaders be more likely to accept their requests.{{sfn|Russett|Oneal|2001}}{{sfn|Lagazio|Russett|2004}}{{sfn|Oneal|Russett|2004}} Weede argues that the pacifying effect of free trade and economic interdependence may be more important than that of democracy, because the former affects peace both directly and indirectly, by producing economic development and ultimately, democracy.{{sfn|Weede|2004}} Weede also lists some other authors supporting this view. However, some recent studies find no effect from trade but only from democracy.{{sfn|Goenner|2004}}{{sfn|Kim|Rousseau|2005}}

None of the authors listed argues that free trade alone causes peace. Even so, the issue of whether free trade or democracy is more important in maintaining peace may have potentially significant practical consequences, for example on evaluating the effectiveness of applying economic sanctions and restrictions to autocratic countries.

It was Michael Doyle who reintroduced Kant's three articles into democratic peace theory. He argued that a pacific union of liberal states has been growing for the past two centuries. He denies that a pair of states will be peaceful simply because they are both liberal democracies; if that were enough, liberal states would not be aggressive towards weak non-liberal states (as the history of American relations with Mexico shows they are). Rather, liberal democracy is a necessary condition for international organization and hospitality (which are Kant's other two articles)—and all three are sufficient to produce peace.<ref name="Doyle 1983"/>{{sfn|Doyle|1997}} Other Kantians have not repeated Doyle's argument that all three in the triad must be present, instead stating that all three reduce the risk of war.

[[Immanuel Wallerstein]] has argued that it is the global capitalist system that creates shared interests among the dominant parties, thus inhibiting potentially harmful belligerence.{{sfn|Satana|2010|p=231}}

[[Toni Negri]] and [[Michael Hardt]] take a similar stance, arguing that the intertwined network of interests in the global capitalism leads to the decline of individual [[Nation-state|nation states]], and the rise of a global [[Empire (Negri and Hardt book)|''Empire'']] which has no outside, and no external enemies. As a result, they write, "The era of imperialist, interimperialist, and anti-imperialist wars is over. (...) we have entered the era of minor and internal conflicts. Every imperial war is a civil war, a police action".{{sfn|Hardt|Negri|2000}}

===Other explanations===
Many studies supporting the theory have controlled for many possible alternative causes of the peace. Examples of factors controlled for are geographic distance, geographic contiguity, power status, alliance ties, militarization, economic wealth and economic growth, power ratio, and political stability. These studies have often found very different results depending on methodology and included variables, which has caused criticism. DPT does not state democracy is the only thing affecting the risk of military conflict. Many of the mentioned studies have found that other factors are also important.{{sfn|Ray|1998}}{{sfn|Ray|2005}}{{sfn|Oneal|Russett|2004}}

Several studies have also controlled for the possibility of reverse causality from peace to democracy. For example, one study supports the theory of simultaneous causation, finding that dyads involved in wars are likely to experience a decrease in joint democracy, which in turn increases the probability of further war. So they argue that disputes between democratizing or democratic states should be resolved externally at a very early stage, in order to stabilize the system.{{sfn|Reuveny|Li|2003}} Another study finds that peace does not spread democracy, but spreading democracy is likely to spread peace. A different kind of reverse causation lies in the suggestion that impending war could destroy or decrease democracy, because the preparation for war might include political restrictions, which may be the cause for the findings of democratic peace.{{sfn|Reiter|2001}} However, this hypothesis has been statistically tested in a study whose authors find, depending on the definition of the pre-war period, no such effect or a very slight one. So, they find this explanation unlikely.{{sfn|Mousseau|Shi|1999}} This explanation would predict a monadic effect, although weaker than the dyadic one.{{dubious|date=January 2016}}

Weart argues that the peacefulness appears and disappears rapidly when democracy appears and disappears. This in his view makes it unlikely that variables that change more slowly are the explanation.{{sfn|Weart|1998}} Weart, however, has been criticized for not offering any quantitative analysis supporting his claims.{{sfn|Ray|2000}}

Wars tend very strongly to be between neighboring states. Gleditsch showed that the average distance between democracies is about 8000 miles, the same as the average distance between all states. He believes that the effect of distance in preventing war, modified by the democratic peace, explains the incidence of war as fully as it can be explained.{{sfn|Gleditsch|1995}}

A 2020 study in ''International Organization'' found that it was not democracy per se that reduces the prospects for conflict, but whether women's suffrage was ensured. The study argued, "women's more pacific preferences generate a dyadic democratic peace (i.e., between democracies), as well as a monadic peace."{{sfn|Barnhart|Trager|Saunders|Dafoe|2020}}

According to [[Azar Gat]]'s ''War in Human Civilization'', there are several related and independent factors that contribute to democratic societies being more peaceful than other forms of governments:{{sfn|Gat|2006}}
#Wealth and comfort: Increased prosperity in democratic societies has been associated with peace because civilians are less willing to endure hardship of war and military service due to a more luxurious life at home than in pre-modern times. Increased wealth has worked to decrease war through comfort.{{sfn|Gat|2006|pp=597–598}}
#Metropolitan service society: The majority of army recruits come from the countryside or factory workers. Many believe that these types of people are suited for war. But as technology progressed the army turned more towards advanced services in information that rely more on computerized data which urbanized people are recruited more for this service.{{sfn|Gat|2006|pp=600–602}}
#Sexual revolution: The availability of sex due to the pill and women joining the labor market could be another factor that has led to less enthusiasm for men to go to war. Young men are more reluctant leave behind the pleasures of life for the rigors and chastity of the army.{{sfn|Gat|2006|pp=603–604}}
#Fewer young males: There is greater life expectancy which leads to fewer young males. Young males are the most aggressive and the ones that join the army the most. With fewer younger males in developed societies could help explain more pacificity.{{sfn|Gat|2006|pp=604–605}}
#Fewer children per family (lower [[fertility rate]]): During pre modern times it was always hard for families to lose a child but in modern times it has become more difficult due to more families having only one or two children. It has become even harder for parents to risk the loss of a child in war. However, Gat recognizes that this argument is a difficult one because during pre modern times the life expectancy was not high for children and bigger families were necessary.{{sfn|Gat|2006|pp=605–606}}
#Women's franchise: Women are less overtly aggressive than men. Therefore, women are less inclined to serious violence and do not support it as much as men do. In liberal democracies women have been able to influence the government by getting elected. Electing more women could have an effect on whether liberal democracies take a more aggressive approach on certain issues.{{sfn|Gat|2006|pp=606–607}}
#Nuclear weapons: Nuclear weapons could be the reason for not having a great power war. Many believe that a nuclear war would result in [[mutually assured destruction]] (MAD) which means that both countries involved in a nuclear war have the ability to strike the other until both sides are wiped out. This results in countries not wanting to strike the other for fear of being wiped out.{{sfn|Gat|2006|pp=608–609}}

===Realist explanations===
Supporters of [[realism in international relations]] in general argue that not democracy or its absence, but considerations and evaluations of power, cause peace or war. Specifically, many realist critics claim that the effect ascribed to democratic, or liberal, peace, is in fact due to alliance ties between democratic states which in turn are caused, one way or another, by realist factors.

For example, Farber and Gowa find evidence for peace between democracies to be statistically significant only in the period from 1945 on, and consider such peace an artifact of the [[Cold War]], when the threat from the communist states forced democracies to ally with one another.{{sfn|Farber|Gowa|1995}} Mearsheimer offers a similar analysis of the Anglo-American peace before 1945, caused by the German threat.{{sfn|Mearsheimer|1990}} Spiro finds several instances of wars between democracies, arguing that evidence in favor of the theory might be not so vast as other authors report, and claims that the remaining evidence consists of peace between allied states with shared objectives. He acknowledges that democratic states might have a somewhat greater tendency to ally with one another, and regards this as the only real effect of democratic peace.{{sfn|Spiro|1994}} Rosato argues that most of the significant evidence for democratic peace has been observed after World War II; and that it has happened within a broad alliance, which can be identified with NATO and its satellite nations, imposed and maintained by American dominance as part of ''[[Pax Americana]]''. One of the main points in Rosato's argument is that, although never engaged in open war with another liberal democracy during the Cold War, the United States intervened openly or covertly in the political affairs of democratic states several times, for example in the [[Chilean coup of 1973]], the [[Operation Ajax]] (1953 coup in Iran) and [[Operation PBSuccess]] (1954 coup in Guatemala); in Rosato's view, these interventions show the United States' determination to maintain an "imperial peace".{{sfn|Rosato|2003}}

The most direct counter arguments to such criticisms have been studies finding peace between democracies to be significant even when controlling for "common interests" as reflected in alliance ties.{{sfn|Gelpi|Griesdorf|2001}}{{sfn|Ray|2003}} Regarding specific issues, Ray objects that explanations based on the Cold War should predict that the Communist bloc would be at peace within itself also, but exceptions include the [[Soviet Invasion of Afghanistan]], the [[Cambodian-Vietnamese War]], and the [[Sino-Vietnamese War]]. Ray also argues that the external threat did not prevent conflicts in the Western bloc when at least one of the involved states was a non-democracy, such as the [[Turkish Invasion of Cyprus]] (against Greek Junta supported Cypriot Greeks), the [[Falklands War]], and the [[Football War]].{{sfn|Ray|1998}} Also, one study notes that the explanation "goes increasingly stale as the post-Cold War world accumulates an increasing number of peaceful dyad-years between democracies".{{sfn|Ravlo|Gleditsch|2000|p=2}} Rosato's argument about American dominance has also been criticized for not giving supporting statistical evidence.{{sfn|Slantchev|Alexandrova|Gartzke|2005}}

Some realist authors also criticize in detail the explanations first by supporters of democratic peace, pointing to supposed inconsistencies or weaknesses.

Rosato criticizes most explanations to how democracy might cause peace. Arguments based on normative constraints, he argues, are not consistent with the fact that democracies do go to war no less than other states, thus violating norms preventing war; for the same reason he refutes arguments based on the importance of public opinion. Regarding explanations based on greater accountability of leaders, he finds that historically autocratic leaders have been removed or punished more often than democratic leaders when they get involved in costly wars. Finally, he also criticizes the arguments that democracies treat each other with trust and respect even during crises; and that democracy might be slow to mobilize its composite and diverse groups and opinions, hindering the start of a war, drawing support from other authors.{{sfn|Rosato|2003}} Another realist, Layne, analyzes the crises and [[brinkmanship]] that took place between non-allied democratic great powers, during the relatively brief period when such existed. He finds no evidence either of institutional or cultural constraints against war; indeed, there was popular sentiment in favor of war on both sides. Instead, in all cases, one side concluded that it could not afford to risk that war at that time, and made the necessary concessions.{{sfn|Layne|1994}}

Rosato's objections have been criticized for claimed logical and methodological errors, and for being contradicted by existing statistical research.{{sfn|Kinsella|2005}} Russett replies to Layne by re-examining some of the crises studied in his article, and reaching different conclusions; Russett argues that perceptions of democracy prevented escalation, or played a major role in doing so.{{sfn|Russett|Layne|Spiro|Doyle|1995}} Also, a recent study finds that, while in general the outcome of international disputes is highly influenced by the contenders' relative military strength, this is not true if both contenders are democratic states; in this case the authors find the outcome of the crisis to be independent of the military capabilities of contenders, which is contrary to realist expectations.{{sfn|Gelpi|Griesdorf|2001}} Finally, both the realist criticisms here described ignore new possible explanations, like the game-theoretic one discussed below.{{sfn|Risse|n.d.}}

===Nuclear deterrent===
A different kind of realist criticism stresses the role of nuclear weapons in maintaining peace. In realist terms, this means that, in the case of disputes between nuclear powers, respective evaluation of power might be irrelevant because of [[Mutual assured destruction]] preventing both sides from foreseeing what could be reasonably called a "victory".{{sfn|Jervis|2002}} The 1999 [[Kargil War]] between India and Pakistan has been cited as a counterexample to this argument,{{sfn|Page Fortna|2004}} though this was a small, regional conflict and the threat of WMDs being used contributed to its de-escalation.{{sfn|''The Nation''|2006}}

Some supporters of the democratic peace do not deny that realist factors are also important.{{sfn|Russett|Layne|Spiro|Doyle|1995}} Research supporting the theory has also shown that factors such as alliance ties and major power status influence interstate conflict behavior.{{sfn|Ray|2003}}