The central claim of a rapidly growing literature in international relations is that members
of pairs of democratic states are much less likely to engage each other in war or in serious
disputes short of war than are members of other pairs of states.
Our analysis does not support this claim. Instead, we ﬁnd that the dispute rate between
democracies is lower than is that of other country pairs only after World War H. Before 1914
and between the World Wars, there is no difference between the war rates of members of
democratic pairs of states and those of members of other pairs of states. We also find that there
is a higher incidence of serious disputes short of war between democracies than between
nondemocracies before 1914.
We attribute this cross-temporal variation in dispute rates to changes in patterns of
common and conflicting interests across time. We use alliances as an indicator of common
interests to show that cross-temporal variation in dispute rates conforms to variations in interest
patterns for two of the three time periods in our sample.