The ?democratic zone of peace? in Europe has expanded on three occasions in the last century, each time as a result of an external shock leading to an ideational vacuum, and each time with the United States (and a growing in?group) as the main promoter of the democratic ideal. The success of the promotion of democracy has on each occasion depended on the successful diffusion of democratic norms and their institutionalisation and internalisation, which has been dependent on receptor states having a rational reason for adopting the new norms. However, the present cycle of democratic enlargement is in danger of ?losing? some prospective states, in particular because the EU enlargement process is delayed. This is having detrimental effects to the diffusion, institutionalisation and internalisation of democratic norms.