This article argues that the balance of evidence and argument supports a shift from the conventional 'separate democratic peace' position that liberal states are peace prone only in relations with other liberal states to the view that they are also more peace prone in relations with non-liberal states than usually thought. The article reviews a range of recent empirical studies that either support or are consistent with this turn and also critiques a number of existing democratic peace theories. Those theories that maintain the view that democracies are peace prone in general are criticized for failing to differentiate the circumstances in which liberal states do and do not go to war. Those theories supporting the predominant 'separate' democratic peace position are criticized for failing to explain why liberal states should be peace prone only in relations with other liberal states. The force of this argument challenges scholars to re-specify the extent {and limitations) ofliberal state peace proneness and to develop a theoretical explanation of this broader but more complex relationship between liberal states and peace.
MacMillan, John (2003) Beyond the Separate Democratic Peace, Journal of Peace Research 40 (2).