This essay suggests that the renewed politicization and militarization of the maritime sphere is a product of the increasing need to re-legitimise the current state-based political order. Order can be understood as particular configurations of boundaries as they define political communities through various practices of inclusion and exclusion: East Asian seas have become one of the final frontiers for sustaining national developmental projects, they mark the boundaries between the Chinese, Japanese, and South Korean nation-states, and are also borderlands in the global order as they separate ‘East’ from ‘West’ and thereby differentiate the ‘civilized’ self from the ‘barbarian’ other.