“…Some doubt their effectiveness (e.g., Michaelowa & Michaelowa, ) or stress their dependency on state‐based forms of governance (e.g., Bulkeley et al, ; Hickmann, ), yet others assert that nonstate actions will contribute to complexity, fragmentation, and possibly undermine governance legitimacy and accountability (Kuyper, Linnér, & Schroeder, ). A growing number of studies, however, take an optimistic, if cautious, view that nonstate action could bridge governance gaps (e.g., Graichen et al, ; Hsu, Cheng, Weinfurter, Xu, & Yick, ; Hsu, Moffat, Weinfurter, & Schwartz, ; Roelfsema, Harmsen, Olivier, Hof, & Van Vuuren, ; Tosun & Schoenefeld, ). While there has been growing optimism, and emphasis on potential and positive signals, few studies look at whether, and under which circumstances, optimistic expectations can be realized.…”