In this article, we re-examine the statistical evidence for the democr
atic peace at the dyadic level. We also investigate the seeming parado
x that democracies are engaged in war as often as autocracies al the n
ation level. From the extensive literature on democracy and peace we h
ave selected as our point of departure two influential contributions (
one by Stuart Bremer, the other by Zeev Maoz & Bruce Russett), both of
which analyse the relationship between democracy and peace at the dya
dic level. Several problematic aspects of these analyses are addressed
; in particular, problems concerning dependence between observational
units caused by continuing war and peace, and by diffusion effects. We
show that the increasing number of countries in the international sys
tem causes their assumption of a stationary probability of war at the
dyadic level to be violated. It is argued that these problems cannot b
e solved adequately within the traditional dyad-year framework. Instea
d, it is proposed to model observations on the interstate dyad as a pr
ocess in continuous time using Cox regression. An extensive model is d
eveloped that controls for contiguity, power status, alliances, stabil
ity, diffusion of war, and recurrence effects. A concept of relevance
is introduced to account for the dependence of the dyadic probability
of war on the size of the international system. The democratic peace i
s supported in our basic model. In a refined model, we find that the t
endency of democracies to join each other in wars is much more marked
than their avoidance of mutual fighting. This explains why democracies
are as war-prone as autocracies.