Assessing the legitimacy of the democratic peace theory is not an examination of whether or not there exists a relationship between the dependent variable, dyadic democratic peace, and the independent variable, dyadic democratic governance. There is a long-established empirical pattern supporting the significantly lower likelihood two democracies engaging in militarized interstate disputes when compared to their autocratic or mixed dyad counterparts. Letzkian and Souva 2009 provide one such iteration of the patterns posited by democratic peace theory, by comprehensively examining data from 1946 to 2000.  While the robustness of the pattern is easily discernable, whether or not this pattern is actually indicative of a correlative or causal relationship has been a matter subject to heavy scrutiny. O’Neal and Russett provide an interesting critique of the relationship between democracy and international peace.

To set the foundations for the critique of O’Neal and Russett’s “The Kantian Peace,” a definition of what exactly the “Kantian Peace” entails must first be established. Kant’s classic argument states that an international perpetual peace can exist if the following features are present: a republican constitution, a federation of interdependent republics, and a commercial spirit. Thus, Kant is not proposing a unilateral relationship with a single independent to dependent variable association; the requirements for Kantian peace necessitate the examination of at least three other independent variables. Accordingly, O’Neal and Russett aim to assess (1) democracy, (2) trade interdependence and (3) IGO involvement, in relation to peace. By performing both dyadic and systemic analyses, O’Neal and Russett ultimately conclude that Kant’s theory was remarkably prescient.

To assess the verity of O’Neal and Russett’s hypotheses, their variables and their respective measures must first be overviewed. They use a single dependent variable, DISPUTE, a dichotomous measure of whether or not there is a militarized interstate dispute (MID), and three Kantian dyadic independent variables: DEM_L, a gradated measure of the level of democracy in the less democratic state of each dyad, DEPEND_L, a gradated measure of the level of dependence of the state less economically dependent on trade, and IGO, a gradated measure of the number of IGOs in which both states in a dyad share membership.

To best dispel the possibility of reverse causality for their purposes, O’Neal and Russett lag all independent variables from the dependent variable by one year. This precaution aims to protect again endogeneity i.e. when conflict may limit trade just as trade may constrain conflict. They also try to control for a variety of realist explanations for dyadic peace, including in their analysis the capability ratio (CAPRATIO), alliance (ALLIES), and contiguity and distance (NONCONTIG and DISTANCE). However, they do not limit the dyads examined to those that are ‘politically relevant,’ a decision which is justified as an attempt to make sure no patterns are overlooked as a result of exclusion. Ergo, in their analysis O’Neal and Russett will also give the overall dyadic results separately from ‘politically relevant’ dyadic results, and compare the two. For the years 1885- 1992, excluding the two world wars and the immediate postwar years (1915-20, 1940-46, O’Neal and Russett observed a total of 150,000 dyads.

To assess their observations, O’Neal and Russett employ a logistic regression analysis. A method of weak-link specification is applied for the DEM_L and DEPEND_L variables, but the IGO variable is inherently dyadic. O’Neal and Russett also assess the realist control variable, to provide the following equation in summation:

(EQ₁) DISPUTE= DEM_L + DEPEND_L + IGO + ALLIES + CAPRATIO + NONCONTIG + DISTANCE + MINORPWRS

As this paper is primarily concerned with the relationship between democracy and peace, the first row of Table 1 is requires the most attention. When considering all dyads in model 1, a higher DEM_L is statistically significant at the .001 level, to a greater likelihood of peace. To test if this relationship exists outside of the cold war era, GEE is used again to re-estimate EQ1 for the years from 1886-1914 and 1921-39 (model 3), and the DEM_L remains significant at the .001 level. To investigate the possible discrepancies between including all possible pairs of states and ‘politically relevant’ dyads, EQ1 is re-estimated a third time, using only ‘politically relevant’ pairs of states, or those that contain at least one major power and those which are contiguous (model 4). Here, the positive relationship between democracy and peace remains apparent (p < .001). The results of this analysis lead to O’Neal and Russett’s conclusions that, compared with the typical dyad, the risk that a more democratic dyad will become engaged in a dispute is reduced by 36 percent, and the same risk for a more autocratic dyad is increased by 56 percent.

One of the other Kantian variables examined in O’Neal and Russett’s piece, trade interdependence (DEPEND_L), takes on especial importance for the purposes of its subsequent comparison with Gartzke’s piece. The GEE estimations posit that the relationship between trade dependence and peace is equally as statistically significant (p < .001) as the relationship between democracy and peace for all dyads for all years[2], and for the pre-Cold War era, and almost as significant (p < .002) for politically relevant dyads[3]. The correlations in realist variables also play a role in the upcoming discussion of Gartzke, with O’Neal and Russett’s results corresponding to all expected patterns:

(1) A preponderance of power rather than a balance deters conflict;

(2) Contiguous states are prone to fight, as are those whose homelands are geographically proximate; and

(3) Major powers are involved in disputes more than are smaller states.

All of these realist variables are significant at the .001 level.  (51)

It is clear from the readings this week that there is an empirically observable relationship between democracy and economic growth. What remains unclear is whether or not this relationship is a causal one. Gerring et al’s piece attempts to establish a number of causal mechanisms linking democracy to economic growth, with the important scope condition of time. The following figure, taken from their article, outlines the main causal mechanisms identified:

The discussion they present of democracies’ creation of physical, human, and social capital do not introduce any new or original ideas. In their discussion of political capital, however, the time factor becomes a subject of emphasis. Democratic political arrangements create a number of political outputs that are assumed to have a direct impact on economic performance, i.e. “market-augmenting economic policies, political stability (understood as a reduction of uncertainty), rule of law, and efficient public bureaucracies.” Valuations of these aspects of political capital are dependent on regime length, which Gerring et al. describes as a. ‘learning’ and b. ‘institutionalization’ processes. In sum, Gerring et al. conclude that, if maintained over time, democracy influences economic performance through four main channels – physical, human, social and political capital- constituting a ‘democratic growth effect.