Democratic political structures
The case for institutional constraints goes back to Kant (1795), who wrote:
"f the consent of the citizens is required in order to decide that war should be declared (and in this constitution it cannot but be the case), nothing is more natural than that they would be very cautious in commencing such a poor game, decreeing for themselves all the calamities of war. Among the latter would be: having to fight, having to pay the costs of war from their own resources, having painfully to repair the devastation war leaves behind, and, to fill up the measure of evils, load themselves with a heavy national debt that would embitter peace itself and that can never be liquidated on account of constant wars in the future"
Democracy thus gives influence to those most likely to be killed or wounded in wars, and their relatives and friends (and to those who pay the bulk of the war taxes) Russett (1993, p. 30). This monadic theory must, however, explain why democracies do attack non-democratic states. One explanation is that these democracies were threatened or otherwise were provoked by the non-democratic states. Doyle (1997, p. 272) argued that the absence of a monadic peace is only to be expected: the same ideologies that cause liberal states to be at peace with each other inspire idealistic wars with the illiberal, whether to defend oppressed foreign minorities or avenge countrymen settled abroad. Doyle also notes (p. 292) liberal states do conduct covert operations against each other; the covert nature of the operation, however, prevents the publicity otherwise characteristic of a free state from applying to the question
Studies show that democratic states are more likely than autocratic states to win the wars. One explanation is that democracies, for internal political and economic reasons, have greater resources. This might mean that democratic leaders are unlikely to select other democratic states as targets because they perceive them to be particularly formidable opponents. One study finds that interstate wars have important impacts on the fate of political regimes, and that the probability that a political leader will fall from power in the wake of a lost war is particularly high in democratic states (Ray 1998).
As described in (Gelpi & Griesdorf 2001), several studies have argued that liberal leaders face institutionalized constraints that impede their capacity to mobilize the state’s resources for war without the consent of a broad spectrum of interests. Survey results that compare the attitudes of citizens and elites in the Soviet successor states are consistent with this argument (Braumoeller 1997). Moreover, these constraints are readily apparent to other states and cannot be manipulated by leaders. Thus, democracies send credible signals to other states of an aversion to using force. These signals allow democratic states to avoid conflicts with one another, but they may attract aggression from nondemocratic states. Democracies may be pressured to respond to such aggression — perhaps even preemptively — through the use of force. Also as described in (Gelpi & Griesdorf 2001), studies have argued that when democratic leaders do choose to escalate international crises, their threats are taken as highly credible, since there must be a relatively large public opinion for these actions. In disputes between liberal states, the credibility of their bargaining signals allows them to negotiate a peaceful settlement before mobilization.
