The democratic peace theory

The democratic peace theory is a relatively new development. One explanation is that democratic governments were scarce before the late 19th century. Although the philosophical idea has circulated since Immanuel Kant, it was not scientifically evaluated until the 1960s.

Immanuel KantKant foreshadowed the theory in his essay Perpetual Peace written in 1795, although he thought that constitutional republics was only one of several necessary conditions for a perpetual peace. Kant's theory was that a majority of the people would never vote to go to war, unless in self defense. Therefore, if all nations were republics, it would end war, because there would be no aggressors. Other explanations have been proposed since, but the modern theory is principally the empirical claim that democracies rarely or never fight (Ray 1998).

Dean Babst, a criminologist, was the first to do statistical research on this topic. He wrote an academic paper supporting the theory in 1964 in Wisconsin Sociologist; he published a slightly more popularized version, in 1972, in the trade journal Industrial Research. Both versions initially received little attention.

Melvin Small and J. David Singer (1976) responded; they found an absence of wars between democratic states with two "marginal exceptions", but denied that this pattern had statistical significance, starting the academic debate. This paper was published in a political science journal which finally brought more widespread attention to the theory, as did Michael Doyle's (1983) lengthy discussion of the topic. Rudolph J. Rummel was another early researcher and drew considerable lay attention to the subject in his later works.

Maoz & Abdolali (1989) extended the research to lesser conflicts than wars. Bremer (1992) and Maoz & Russett (1992) found the correlation between democracy and peacefulness remained significant after controlling for many possible confounding variables. This moved the theory into the mainstream of social science. Supporters of Realism in international relations and others responded by raising many new objections. Other researchers attempted more systematic explanations of how democracy might cause peace (Kochler 1995), and of how democracy might also affect other aspects of foreign relations such as alliances and collaboration (Ray 2003).

There have been numerous further studies in the field since these pioneering works.[2] Most studies have found some form of democratic peace exists, although neither methodological disputes nor doubtful cases are entirely resolved (Kinsella 2005).