The research project examined the influence national parliaments can exert over the deployment of armed forces. To this end, an original data set, "ParlCon", was created which contains information about the rights of national parliaments concerning the deployment of military forces for all democracies worldwide. On this basis, explanations were sought as to why parliamentary rights differ considerably between democracies. Parliaments are commonly considered key institutions for the democratic peace as they ensure that government policy is linked to the populace, which is generally assumed to be peace-inclined. However, not in all democracies do parliaments possess such comprehensive influence when it comes to the deployment of the military. Only in some democracies does the government need parliamentary consent prior to the deployment of armed forces, while in others it can take such a decision single-handedly.

The "ParlCon" data set contains information for parliaments in 49 democracies for the time period from 1989 to 2004. On the basis of this data, it can be demonstrated that differences in parliamentary rights are largely due to three factors: A significant external threat as well as a historical connection to the British constitutional tradition contribute to the limitation of parliamentary influence. In contrast, states which suffered high losses due to lost wars in the past, tend to provide parliament with a veto right over military deployment.

The project was conducted in cooperation with Prof Dr Wolfgang Wagner (Free University Amsterdam), funded by the German Foundation for Peace Research (Deutsche Stiftung Friedensforschung, DSF) and concluded in 2010.