According to the constructivist theory of liberal democratic peace, intersubjective social realities are often more important in the construction of pacific unions of interstate peace. In order to demonstrate the importance of social construction rather than objective matters as a source of peace, previous studies have discussed cases where democracies appear to have fought one another. This article, instead of showing how objective factors fail to contribute to liberal democratic peace if the intersubjective consensus is lacking, shows how the intersubjective consensus about the common interests, norms, and identity has contributed to the interstate peace among the illiberal non-democracies of Southeast Asia. The long peace among the members of the Association of Southeast Asian Nations in 1968-94 is compared to the bellicose period of the Malaysian confrontation, when most of the objective bases for the perception of common interests, common commitment to democratic procedures and liberal norms, and institutional restraints on war were arguably stronger than during the long peace. The intention is to show how even the political elite groups of illiberal non-democracies can manipulate the social consciousness for the purpose of creating a pacific union, similar to the one which has been socially constructed by liberal democracies. At the same time the study provides indirect support for the constructivist theory of liberal democratic peace.