The Choice for Peace 
The Validity of the Democratic Peace Theory 

The democratic peace theory, which states that democratic or liberal states rarely fight interstate wars against each other, is the most law-like empirical finding generated by the discipline of international relations. Repeated studies in the international relations of war dyads (pairs of states that wage a war against each other), demonstrate that "[t]he number of wars between the democracies during the past two centuries ranges from zero to less than a handful depending on precisely how democracy is defined" (Levy, 1989, pp. 87-88). This absence of wars between democracies is the most important evidence supporting the democratic peace theory and probably accounts for its prominence in the last fifty years. Beyond the empirical evidence supporting the theory, there exists no consensus on the validity of the assertion of democratic peace especially because the theory suggests that a world, which only consists of democratic states, will be peaceful. This essay focusses on the discussion of the validity of the democratic peace theory by highlighting the logic behind the democratic peace theory in order to give an overview of the current debate. 
  Advocates of the democratic peace theory have discovered a powerful empirical generalization; in the last two centuries democracies did not fight each other. The methods of testing the significance of this finding have evolved over time from the original basic inquiry of Babst (1964; 1972) into increasingly complex data sets including all possible dyads between the nineteenth century and the late twentieth century (e.g., Bremmer, 1992, 1993; Dixon, 1994; Moaz and Russett, 1992, 1993; Owen, 1994; Russett 1993; Russett and O'Neal, 1999, 2001; Small and Singer, 1976).  Although several attempts have been conducted to challenge these findings  (e.g., Farber and Gowa, 1997; Layne 1994; Spiro 1994), the correlation between domestic regime type and warfare remains robust while controlling for additional factors like contiguity, power status, alliance ties, militarization, economic development and political stability. Interestingly, this does not suggest that democracies are more pacific in general than non-democracies; democratic states are involved in war as often as states with other regime types (e.g., Chan, 1984; Doyle, 1983; Maoz and Abdolali, 1989; Morgan, 1991; Senese, 1997; Small and Singer, 1976; Wright, 1942). What is most striking is which aspects of the internal composition of democratic states prevent those states from fighting one another despite the fact that they are not less war-prone than non-democracies.
  The logic behind the fact that democracies will not go to war with each other exists of two broad causal logics, a normative and an institutional one. The former states that democratic political leaders act on the basis of democratic norms whenever possible emphasizing regulated political competition through peaceful means, which lead them to prefer non-violent conflict resolution rather than elimination of their opponents (Moaz, 1993, p. 625; Rosato, 2003, 586). This general normative orientation is then shared by democracies in international politics resulting in both trust and respect for one another, which derives from the expectation that the other state adheres to the same norms. These norms proscribed democratic states from using violence leading any two democracies to prevent violent conflicts. However, the fact remains that the international system is characterized by anarchy determining that states put their own survival above any other value they seek to promote. Hence democracies are just as likely to shift norms for their own sake as non-democracies will do.  
  According to the institutional logic, democratic leaders are made accountably by democratic institutions and processes, which constrain leaders from engaging in warfare or conflict (Moaz, 1993, pp. 625-626; Rosato, 2003, pp. 586-587). This accountability derives from the fact that political leaders want to remain in office, that the opposition would use unpopular policies against them and that it is possible for democratic societies to remove leaders who have not acted in their interests. Moreover, several characteristics of democracies, such as freedom of speech and open political processes, make it possible for voters to rate the performances of political leaders, which makes democratic leaders more conscious to engage in large scale violence if there is no support for their actions. It is the mobilization of both the general public opinion as a variety of democratic institutions, for instance the legislature, the political bureaucracies, and key interest groups, that is required for international action in a democratic political system. Inevitably, this leads to less possibilities justifying and fighting wars in democracies. In contrast, when non-democratic leaders secured the support of the key legitimizing group, the government could launch its policy with little regard to the opinion of the general public or other actors of the political system.  
  In Doyle's view (1983 and 2005), it is liberal practice that "may reduce the probability that states will successfully exercise the consistent restraint and peaceful intentions that a world peace may well require" (Doyle, 1983, p. 206).  He states that the exceptional nature of liberal pacification was already predicted by Immanual Kant in his "Perpetual Peace" (1795/1917), which states that peace among states will be guaranteed when three definitive articles of peace by all nations: "[t]he civil constitution of the state should be republican" (Kant, 1795/1917, p. 120), "[t]he law of nations should be founded on a federation of free states" (Kant, 1795/1917, p. 128) and "[t]he rights of men, as citizens of the world, shall be limited to conditions of universal hospitality" (Kant, 1795/1917, p. 137). Kant's first article shared some characteristics with the institutional logic mentioned earlier by focussing on "republican caution" (Doyle, 2005, p. 464) instead of "autocratic caprice" (Doyle, 2005, p. 464). Besides, representation should ensure that wars are only fought by democracies to encourage freedom, protect private property and to assist other liberal states in their defence against non-liberal enemies (Doyle, 2005, p. 464). It should be stressed that the concept of representation will not eliminate wars between liberal and non-liberal state, although this could bring peace among democratic states.  
  The second article highlights that a federation of states which is limited to republics, "maintains itself, prevents war, and steadily expands", causing slowly that more and more states have been taught "the lessons of peace" (Doyle, 1983, p. 226). It is not any group of states with similar political structure and values that would be peaceful, but it is especially, as Doyle argues, the democratic federation that prevents states to fight with each other and that creates a collective security agreement among those states (Doyle, 1983, pp. 222-224). The third and last article proscribes what Kant (1795/1917) so aptly terms "a cosmopolitan law", which focuses on hospitality by recognizing the rights of citizens from other states when they arrive in another state. Besides the right of access, this hospitality also includes the obligation of maintaining the possibilities for citizens to exchange goods and ideas, which creates an international division of labour and free trade depending on the cooperation and interdependent states (Doyle, 2005, pp. 464-465). None of these articles, as Doyle correctly points out, is alone sufficient enough to secure peace, but together they connect the characteristics of liberal states and economies which will sustain liberal peace. 
  The above characteristics are in line with the empirical findings reported by Russett and O'Neal (2001) who combines the normative and institutional logic with the "Kantian tripod" for peace in a single study by examining both the pacifying effects of democratic regimes, as the pacifying effects of economic interdependence and participation in international organizations. It is worth pointing out that such a study which combines all the above characteristics is new in the current discussion. Russett and O'Neal's study differs from most studies by examine only the politically relevant dyads from 1886 to 1992, which are characterized either by territorial contiguity or inclusion of a great power. By focusing only on the relevant dyads, Russett and O'Neal's findings are almost inevitable must more accurate than by using all possible dyads in a given period. In short, their various analyses show that even after controlling for the lurking variables mentioned earlier, "two democracies are 33 per cent less likely than the average dyad to become involved in a militarised dispute", which they argue is a conservative judgement of the "pacific benefits of democracy" (Russett and O'Neal, 2001, p.275). Their analyses show further that states which are more economically interdependent, have a lower risk of becoming involved in disputes. The same causal relation exists between the memberships in international organizations two states share and the risk of becoming involved in disputes. Not only may this prove that all these three effects reduce the likelihood of a dispute under certain specified conditions between two interdependent democracies (Russett and O'Neal, 2001, p. 282), but also that both the normative and institutional logic, as the Kantian tripod are likely to be true. 
  A clearly different position is taken by Rosato, who argues that the logic behind the democratic peace theory is flawed. ...




References
Babst, D.Y. (1964). Elective Governments - A Force for Peace. The Wisconsin Sociologist, 3, 9-14. 
Bremer, Stuart A. (1992). Dangerous Dyads: Conditions Affecting the Likelihood of Interstate War, 1816-1965. Journal of Conflict Resolution, 36, 309-341 
Bremer, Stuart A. (1993). Democracy and Militarized Interstate Conflict. International  Interactions, 18, 231-249. 
Chan, S. (1984). International Relations in Perspective: the Pursuit of Security, Welfare and  Justice. New York: Macmillan. 
Dixon, William J. (1994). Democracy and the Peaceful Settlement of International Conflict.  American Political Science Review, 88(1), 14-32. 
Doyle, Michael W. (1983). Kant, Liberal Legacies, and Foreign Affairs. Reprinted in Brown,  M.E., Lynn-Jones, S.M. & Miller, S.E. (eds) (1996), Debating the Democratic Peace,  Cambridge. MA: MIT Press. 
Farber, H., & Gowa, J. (1997). Common interests or common polities? Reinterpreting the  democratic peace. Journal of Political Sciences, 59, 393-417. 
Kant, I. (1917). Perpetual Peace: A Philosophical Essay (M. Campbell Smith, Trans.). New York, NY; the Macmillan Company. (Original work published 1795). 
Levy, J.S. (1989). Domestic Politics and War. In Rothberg, R.I., & Rabb, T.K. (eds.), The  Origin and Prevention of Major Wars. Cambridge: Cambridge University Press. 
Maoz, Z., & Abdolali, N. (1989). Regime types and international conflict 1816-1976. Journal of Conflict Resolutions, 33, 3-35 
Maoz, Z., & Russett, B. (1992). Alliance, contiguity, wealth and political stability: Is the lack  of conflict among democracies a statistical artifact? Internationa Interaction, 17, 245- 267. 
Maoz, Z., & Russett, B. (1993). Normative and structural causes of democratic peace.  American Political Science Reviewed, 87, 624-638.  
Owen, John M. (1994). How Liberalism Produces Democratic Peace. Reprinted in Brown,  M.E., Lynn-Jones, S.M. & Miller, S.E. (eds) (1996), Debating the Democratic Peace.  Cambridge, MA: MIT Press. 
Rosato, Sebastian (2003). The Flawed Logic of Democratic Peace Theory. American Political  Science Review, 97(4), 585-602. 
Russett, Bruce (1993). Why Democratic Peace? Reprinted in Brown, M.E., Lynn-Jones, S.M.  & Miller, S.E. (eds) (1996), Debating the Democratic Peace. Cambridge, MA: MIT  Press. 
Senese, P.D. (1997). International sources of dispute challenges and reciprocation. Journal of  Conflict Resolutoions, 41,407-427. 
Small, M., & Singer, J.D. (1976). The war-proneness of democratic regimes 1816-1965.  Journal of International Relations, 1, 50-69. 
Spiro, D.E. (1994). The insignificance of the liberal peace. International Security, 19, 50-86.
Wright, Q. (1942). A Study of War. Chicago: University Chicago Press.