The Sunflower Movement will go down in Taiwan’s history as one of the most significant incidents in the 21st century, yet we are only beginning to understand its significance. I use Weingast’s theory of democratic consolidation to argue that the Cross-Strait Service Pact crossed the limit of the institutional capacity of TW’s constitutional design, exposing tension in TW’s identity politics. The Movement is the manifestation of the rationality of fear in response to the breaking point of tension. The breaking of TW’s constitutional structure has two deeper roots: 1) democratization in TW has not solved the national identity conflict; 2) a rising need to assert Taiwanese identity nurtures the conception of majoritarian democracy. The tricky thing about TW’s post-transition democratic politics is that political conflict must be managed under the rule of law, which lacks a solid political foundation in TW. Unlike in HK, TW’s rule of law lacks a source of legitimacy standing on its own.