In the wake of the emergence of Social Constructivism, the development of International Relations theory has entered into a new phase. Researchers often address the subject in terms of the historical evolution of theories with reference to the Great Debates since Classical Realism-vs.-Idealism. As such, Social Constructivism, often regarded as a recent import from sociological perspectives, is commonly differentiated from (Neo)Realism and Neoliberalism. Among them, Neoliberalism is often tantamount to “new institutionalism” in International Relations. Some analysts therefore concluded that Social Constructivism differs from New Institutionalism and even went further to maintain that the former transcends the latter in terms of the consistency of ontology and epistemology. From the perspective of New Institutionalism of Sociological and Organizational Analysis (SOA) branch, the common distinction between Social Constructivism and New Institutionalism in IR is problematic and deserves re-examination.

In this paper, it is argued from the SOA new institutionalist perspective that there is close linkage between Social Constructive in IR and SOA new institutionalism: both share certain commonalities and complements with each other. IR theorists may well clarify the types of new institutionalisms referred to when dealing with the relationships between new institutionalism and social constructivism. The linkage per se can also be demonstrated in the case of Beijing-Taipei diplomatic practices on "one China".