Add to ORKGWhat determines the choice of a nation state to form, to join, or to remain in a trans-national regional organization (TRO), and how and why does the nature of its political regime matter? This theoretical paper analyzes the relationship between different types of national regimes and their likely strategies with regard to regionalism in post-Cold War period. “Real existing democracies” and “real existing autocracies” are confronted with the prospects of entering into and supporting arrangements for regional integration and/or regional cooperation. It attempts to answer the theoretical questions: (1) What determines such a choice; and (2) How much the difference in regime type contributes to it. The paper aims to contribute to the literatur...