“…Finally, successful institutional formation requires that states join the institutions they negotiate. Both state and treaty characteristics help explain membership choices (Seelarbokus 2014b). Although most of the literature examines correlations between national economic and political traits and treaty membership, increasing attention is being paid to treaty design features such as legalization, formalization and obligational depth (Von Stein 2008;Perrin and Bernauer 2010;Baccini and Urpelainen 2014;Seelarbokus 2014b;Spilker and Koubi 2016).…”