About 200 years after the emergence of Kant’s theory, it turns out that political scientists who work in international relations have come to the conclusion that this theory is correct, according to the data they have thus far. This is surprising: the dominant theory in international relations—so-called “realism”—has no explanation for this data. Realism posits that states, in foreign policy, act exclusively according to their own national interests, so that, without any supra-national body, there is a sort of Hobbesian state of nature, in which conflicts, according to the interests of the states involved, can escalate into wars, regardless of the sort of constitutions these states have.
Against this view, Kant maintained that democracies (“Republics”) would not go to war against one another, because the interests of the ruling bodies within these democracies are generally identical with the interests of those who are governed by them, because the worth of the individual has become a part of the understanding of the state, and because—and here is the crucial point for us—the international relationships in democracies are public: there aren’t any secret subsidiary agreements to international treaties; for every citizen, everything is transparent and can be checked on, and those who rule in democracies tend to avoid all duplicity and secret policies. This condition of publicity constitutes the centerpiece of Kant’s democratic peace: The democratic form of government will ensure peace between republics, independent of their particular interests, only when the goals and praxis of regimes in international politics are transparent and public.