Whereas social theory focuses on the common welfare in Catholic social teaching, certain approaches in liberalism contest the possibility and the necessity of the orientation toward public welfare. This book develops elements of a theory of common welfare and describes its importance for politics, the economy, the law and psychology. Based on examples such as divorce, political secession and the schism, it analyzes the relevance of the separation of unions or communities for the common welfare and shows that the concept of common welfare is indispensable for social theory today as well.